Resist composition and patterning process

ABSTRACT

A resist composition containing: (A) a resin containing a repeating unit having an acid-labile group; (B) a photo-acid generator shown by a general formula (B-1); and (C) a solvent, where W 1  represents a cyclic divalent hydrocarbon group having 4 to 12 carbon atoms and containing a heteroatom; W 2  represents a cyclic monovalent hydrocarbon group having 4 to 14 carbon atoms and not containing a heteroatom; Rf represents a divalent organic group shown by the following general formula; and M +  represents an onium cation. This provides a resist composition and a patterning process that uses the resist composition that show a particularly favorable mask dimension dependency (mask error factor: MEF), LWR, and critical dimension uniformity (CDU) particularly in photolithography where a high-energy beam such as an ArF excimer laser beam is used as a light source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 17/082,175,filed Oct. 28, 2020, which in turn claims priority to Japanese PatentApplication Number 2019-202291, filed Nov. 7, 2019. These applicationsare incorporated by reference herein in their entireties.

TECHNICAL FIELD

The present invention relates to a resist composition and a patterningprocess.

BACKGROUND ART

As LSIs advance toward higher integration and higher processing speed,miniaturization is progressing rapidly. As a cutting-edge technology forminiaturization, mass production by ArF immersion lithography whereexposure is performed with a liquid such as water placed between aprojection lens and a substrate is conducted, and studies have beenconducted on multiple exposure (multiple patterning) of ArF lithographyand extreme ultraviolet ray (EUV) lithography with a wavelength of 13.5nm, etc.

Among chemically amplified resist materials used for the above-describedlithography, a compound that is decomposed by exposure and generatesacid (hereinafter referred to as “acid generator”) is used, and aciddiffusion can be suppressed by optimizing the structure in the acidgenerator, and it becomes possible to form high-resolution patterns. Assuch acid generators, those disclosed in Patent Documents 1 to 4 arebeing studied, for example.

CITATION LIST Patent Literature

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 2008-074843

Patent Document 2: Japanese Unexamined Patent Application PublicationNo. 2009-191054

Patent Document 3: Japanese Unexamined Patent Application PublicationNo. 2011-126869

Patent Document 4: Japanese Unexamined Patent Application PublicationNo. 2012-072108

SUMMARY OF INVENTION Technical Problem

On advancing further miniaturization, conventionally studied acidgenerators are not necessarily sufficient regarding various propertiesincluding resolution and resist pattern shape.

The present invention has been made to solve the above-describedproblems, and an object thereof is to provide a resist composition and apatterning process that show a favorable mask dimension dependency (maskerror factor: MEF), Line Width Roughness (LWR), and critical dimensionuniformity (CDU) in photolithography.

Solution to Problem

To achieve the object, the present invention provides a resistcomposition comprising:

(A) a resin containing a repeating unit having an acid-labile group;

(B) a photo-acid generator shown by a general formula (B-1); and

(C) a solvent,

wherein W₁ represents a cyclic divalent hydrocarbon group having 4 to 12carbon atoms and containing a heteroatom; W₂ represents a cyclicmonovalent hydrocarbon group having 4 to 14 carbon atoms and notcontaining a heteroatom; Rf represents a divalent organic group shown bythe above general formula; A₁ and A₂ each independently represent ahydrogen atom or a trifluoromethyl group; B₁ and B₂ each independentlyrepresent a hydrogen atom, a fluorine atom, or a trifluoromethylgroup; * represents an attachment point for a carbonyloxy group; “m”represents an integer of 0 to 4; “n” represents an integer of 0 or 1;and M⁺ represents an onium cation.

The inventive resist composition as described shows favorable maskdimension dependency (mask error factor: MEF), LWR, and criticaldimension uniformity (CDU) in photolithography.

In this case, W₁ in the general formula (B-1) preferably represents acyclic divalent hydrocarbon group containing a lactone ring structurehaving 6 to 12 carbon atoms.

Such a resist composition makes it possible to further suppress aciddiffusion by having a lactone ring arranged in a position near asulfonic acid group at the time of acid generation after exposure.Therefore, the resist composition can show a more favorable maskdimension dependency, LWR, and critical dimension uniformity.

Furthermore, W₂ in the general formula (B-1) preferably represents apolycyclic monovalent hydrocarbon group having 7 to 14 carbon atoms andnot containing a heteroatom.

Such a resist composition makes it possible to provide a suitablesolubility since a highly annelated hydrocarbon group is arranged at aterminal. Therefore, the resist composition can show an even morefavorable mask dimension dependency, LWR, and critical dimensionuniformity.

Furthermore, the group Rf in the general formula (B-1) is preferablyselected from groups shown by the following formulae (Rf-1) to (Rf-6),

wherein * represents an attachment point for a carbonyloxy group.

Such a resist composition can show a more favorable mask dimensiondependency, LWR, and critical dimension uniformity since solubility isenhanced by the effect of the fluorine atom in Rf, and a sulfonic acidthat is generated after exposure comes to have a suitable acidity.

The above-described resist composition preferably further comprises as acomponent (D), a resin being a fluorine-containing resin having at leastone repeating unit selected from repeating units shown by the followingformulae (D-1), (D-2), and (D-3), wherein the resin is different fromthe resin of the component (A),

wherein R^(A) each independently represents a hydrogen atom or a methylgroup; R⁵¹ and R⁵² each independently represent a hydrogen atom or alinear, branched, or cyclic monovalent hydrocarbon group having 1 to 10carbon atoms; R⁵³ represents a single bond or a linear or brancheddivalent hydrocarbon group having 1 to 5 carbon atoms; R⁵⁴, R⁵⁵, and R⁵⁶each independently represent a hydrogen atom, a linear, branched, orcyclic monovalent hydrocarbon group, fluorinated monovalent hydrocarbongroup, or acyl group having 1 to 15 carbon atoms, or an acid-labilegroup; when R⁵⁴, R⁵⁵, and R⁵⁶ represent the monovalent hydrocarbon groupor the fluorinated monovalent hydrocarbon group, some carbon atomsthereof are optionally substituted with an ether group or a carbonylgroup; R⁵⁷ represents a linear, branched, or cyclic hydrocarbon group orfluorinated hydrocarbon group with a valency of (v+1) having 1 to 20carbon atoms; and “v” represents an integer of 1 to 3.

When the inventive resist composition further contains such a component(D), the contact angle between a resist film surface and waterincreases, and defects due to remaining immersion liquid and elution ofan acid generator or a quencher can be suppressed. In addition, itbecomes possible to adjust the solubility of the resist film surface,and a favorable critical dimension uniformity can be achieved.

Furthermore, the present invention provides a patterning processcomprising the steps of:

forming a resist film by coating a substrate with the above-describedresist composition and heat-treating;

exposing the resist film with a high-energy beam; and

developing the exposed resist film using a developer.

Such a patterning process can achieve a favorable mask dimensiondependency, LWR, and critical dimension uniformity in photolithography.

In the inventive patterning process, the high-energy beam can be an ArFexcimer laser with a wavelength of 193 nm or a KrF excimer laser with awavelength of 248 nm.

Furthermore, the patterning can be performed with the exposure as animmersion exposure performed with a liquid having a refractive index of1.0 or more placed between the resist film and a projection lens, andwith a protective film further formed on the resist film, and immersionexposure performed with the liquid placed between the protective filmand the projection lens.

Such a patterning process makes it possible to form a pattern excellentin MEF, LWR, and CDU with a more favorable sensitivity.

Furthermore, in the inventive patterning process, the high-energy beamcan be an electron beam or an extreme ultraviolet ray with a wavelengthof 3 to 15 nm.

Such a patterning process can also achieve a favorable mask dimensiondependency, LWR, and critical dimension uniformity.

Advantageous Effects of Invention

The inventive resist composition makes it possible to form a resistpattern excellent in mask dimension dependency (mask error factor: MEF)and LWR, in particular.

The present invention can provide a resist composition and a patterningprocess that show a favorable mask dimension dependency (mask errorfactor: MEF), LWR, and critical dimension uniformity (CDU) particularlyin photolithography where an ArF excimer laser is used as a lightsource.

Furthermore, the inventive resist composition has both a favorablesensitivity and pattern shape, and is suitable as a material for ArFimmersion lithography. In particular, the inventive resist compositionis useful for various development processes since the inventive resistcomposition has a favorable sensitivity and is excellent in MEF, etc. inboth positive patterning by alkaline development and negative patterningby organic solvent development.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a ¹HNMR spectrum of PAG 1 obtained in Example 1-1.

FIG. 2 shows a ¹⁹FNMR spectrum of PAG 1 obtained in Example 1-1.

DESCRIPTION OF EMBODIMENTS

As described above, on advancing further miniaturization, conventionallystudied acid generators are not necessarily sufficient regarding variousproperties including resolution and resist pattern shape.

To achieve the above object, the present inventors have earnestlystudied and found out that a resist composition including an acidgenerator shown by the following formula (B-1) shows a favorable MEF,LWR, and CDU, and is extremely effective for a precise and fineprocessing.

That is, the present invention is a resist composition comprising:

(A) a resin containing a repeating unit having an acid-labile group;

(B) a photo-acid generator shown by a general formula (B-1); and

(C) a solvent,

wherein W₁ represents a cyclic divalent hydrocarbon group having 4 to 12carbon atoms and containing a heteroatom; W₂ represents a cyclicmonovalent hydrocarbon group having 4 to 14 carbon atoms and notcontaining a heteroatom; Rf represents a divalent organic group shown bythe above general formula; A₁ and A₂ each independently represent ahydrogen atom or a trifluoromethyl group; B₁ and B₂ each independentlyrepresent a hydrogen atom, a fluorine atom, or a trifluoromethylgroup; * represents an attachment point for a carbonyloxy group; “m”represents an integer of 0 to 4; “n” represents an integer of 0 or 1;and M⁺ represents an onium cation.

Hereinafter, the present invention will be described in detail, but thepresent invention is not limited thereto. Note that regarding chemicalstructure in the following chemical formulae, an enantiomer or adiastereomer can exist in many cases, but in all cases, each chemicalformula represents all of these stereoisomers as long as there is nomention to the contrary. In addition, these stereoisomers may be usedalone or as a mixture.

[Resist Composition]

The inventive resist composition contains:

(A) a resin containing a repeating unit having an acid-labile group;

(B) a photo-acid generator shown by a general formula (B-1); and

(C) a solvent. Furthermore, other components such as a specificfluorine-containing resin different from the resin of the component (A)as a component (D), a quencher, and a surfactant may be contained asnecessary. Hereinafter, each component will be described.

[(A) Base Resin]

In the inventive resist composition, the base resin (resin A) of thecomponent (A) contains a repeating unit having an acid-labile group anddoes not contain a repeating unit having an aromatic substituent exceptfor the repeating unit having the acid-labile group.

Examples of the repeating unit having an acid-labile group in the baseresin of the component (A) include the following general formula (a1):

where R¹ represents a hydrogen atom or a methyl group; and X representsan acid-labile group.

The repeating unit shown by the general formula (a1) is decomposed bythe action of an acid to generate a carboxylic acid, and provides analkali-soluble polymer. Various kinds may be used as the acid-labilegroup X, and specific examples include groups shown by the followinggeneral formulae (L1) to (L9), a tertiary alkyl group having 4 to 20carbon atoms, preferably 4 to 15 carbon atoms, a trialkylsilyl groupwith each alkyl group having 1 to 6 carbon atoms, and an oxoalkyl grouphaving 4 to 20 carbon atoms.

Here, the dotted line represents an attachment point (the same shallapply hereinafter).

In the formula (L1), R^(L01) and R^(L02) represent a hydrogen atom or alinear, branched, or cyclic alkyl group having 1 to 18, preferably 1 to10 carbon atoms, and specific examples include a methyl group, an ethylgroup, a propyl group, an isopropyl group, an n-butyl group, a sec-butylgroup, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a2-ethylhexyl group, an n-octyl group, a norbornyl group, atricyclodecanyl group, a tetracyclododecanyl group, and an adamantylgroup. R^(L03) represents a monovalent hydrocarbon group having 1 to 18,preferably 1 to 10 carbon atoms optionally having a heteroatom such asan oxygen atom; and may be exemplified by a linear, branched, or cyclicalkyl group, and those with a part of hydrogen atoms of these groupssubstituted with a hydroxy group, an alkoxy group, an oxo group, anamino group, an alkylamino group, etc. Specific examples include thefollowing substituted alkyl groups.

R^(L01) and R^(L02), R^(L01) and R^(L03), and R^(L02) and R^(L03) may bemutually bonded to form a ring with the carbon atom or the oxygen atomto which they are bonded. When the ring is formed, R^(L01), R^(L02), andR^(L03) each represent a linear or branched alkylene group having 1 to18, preferably 1 to 10 carbon atoms.

In the formula (L2), R^(L04) represents a tertiary alkyl group having 4to 20, preferably 4 to 15 carbon atoms, a trialkylsilyl group each alkylgroup of which has 1 to 6 carbon atoms, an oxoalkyl group having 4 to 20carbon atoms, or the group represented by the general formula (L1).Specific examples of the tertiary alkyl group include a tert-butylgroup, a tert-amyl group, a 1,1-diethylpropyl group, a2-cyclopentylpropane-2-yl group, a 2-cyclohexylpropane-2-yl group, a2-(bicyclo[2.2.1]heptan-2-yl)propane-2-yl group, a2-(adamantane-1-yl)propane-2-yl group, a 1-ethylcyclopentyl group, a1-butylcyclopentyl group, a 1-ethylcyclohexyl group, a 1-butylcyclohexylgroup, a 1-ethyl-2-cyclopentenyl group, a 1-ethyl-2-cyclohexenyl group,a 2-methyl-2-adamantyl group, and a 2-ethyl-2-adamantyl group. Specificexamples of the trialkylsilyl group include a trimethylsilyl group, atriethylsilyl group, and a dimethyl-tert-butylsilyl group. Specificexamples of the oxoalkyl group include a 3-oxocyclohexyl group, a4-methyl-2-oxooxan-4-yl group, and a 5-methyl-2-oxooxolan-5-yl group.“1” represents an integer of 0 to 6.

In the formula (L3), R^(L05) represents a linear, branched, or cyclicalkyl group having 1 to 8 carbon atoms which may be substituted, or anaryl group having 6 to 20 carbon atoms which may be substituted.Specific examples of the alkyl group which may be substituted includelinear, branched, or cyclic alkyl groups such as a methyl group, anethyl group, a propyl group, an isopropyl group, an n-butyl group, asec-butyl group, a tert-butyl group, a tert-amyl group, an n-pentylgroup, an n-hexyl group, a cyclopentyl group, and a cyclohexyl group,and those with a part of hydrogen atoms of these groups substituted witha hydroxy group, an alkoxy group, a carboxyl group, an alkoxycarbonylgroup, an oxo group, an amino group, an alkylamino group, a cyano group,a mercapto group, an alkylthio group, a sulfo group, etc. Specificexamples of the aryl group which may be substituted include a phenylgroup, a methylphenyl group, a naphthyl group, an anthryl group, aphenanthryl group, and a pyrenyl group. In the formula (L3), “m”represents 0 or 1, “n” represents any one of 0, 1, 2, and 3, and “m” and“n” are numbers satisfying 2m+n=2 or 3.

In the formula (L4), R^(L06) represents a linear, branched, or cyclicalkyl group having 1 to 8 carbon atoms which may be substituted or anaryl group having 6 to 20 carbon atoms which may be substituted, andspecific examples include the same substances as exemplified forR^(L05). R^(L07) to R^(L16) each independently represent a hydrogen atomor a monovalent hydrocarbon group having 1 to 15 carbon atoms. Specificexamples thereof include linear, branched, or cyclic alkyl groups suchas a methyl group, an ethyl group, a propyl group, an isopropyl group,an n-butyl group, a sec-butyl group, a tert-butyl group, a tert-amylgroup, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonylgroup, an n-decyl group, a cyclopentyl group, a cyclohexyl group, acyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutylgroup, a cyclohexylmethyl group, a cyclohexylethyl group, and acyclohexylbutyl group, and those with a part of hydrogen atoms of thesegroups substituted with a hydroxy group, an alkoxy group, a carboxylgroup, an alkoxycarbonyl group, an oxo group, an amino group, analkylamino group, a cyano group, a mercapto group, an alkylthio group, asulfo group, etc. R^(L07) to R^(L16) may be bonded with each other toform a ring (for example, R^(L07) and R^(L08), R^(L07) and R^(L09),R^(L08) and R^(L10), R^(L09) and R^(L10), R^(L11) and R^(L12), andR^(L13) and R^(L14)). In this case, these represent divalent hydrocarbongroups having 1 to 15 carbon atoms, and may be specifically exemplifiedby substances obtained by removing one hydrogen atom from theabove-exemplified monovalent hydrocarbon group. In addition, two ofR^(L07) to R^(L16) that are attached to adjacent carbon atoms may bemutually bonded without any interposition to form a double bond (forexample, R^(L07) and R^(L09), R^(L09) and R^(L15), and R^(L13) andR^(L15)).

In the formula (L5), R^(L17), R^(L18), and R^(L19) each independentlyrepresent a linear, branched, or cyclic alkyl group having 1 to 15carbon atoms. Specific examples include a methyl group, an ethyl group,a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group,a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a2-ethylhexyl group, an n-octyl group, a 1-adamantyl group, and a2-adamantyl group.

In the formula (L6), R^(L20) represents a linear, branched, or cyclicalkyl group having 1 to 10 carbon atoms which may be substituted, or anaryl group having 6 to 20 carbon atoms which may be substituted, andspecific examples include those the same as R^(L05).

In the formula (L7), R^(L21) represents a linear, branched, or cyclicalkyl group having 1 to 10 carbon atoms which may be substituted, or anaryl group having 6 to 20 carbon atoms which may be substituted, andspecific examples include those the same as R^(L05).

R^(L24) represents a divalent group that forms a substituted orunsubstituted cyclopentane ring, cyclohexane ring, or norbornane ringwith a carbon atom bonded to R^(L24). R^(L22) and R^(L23) eachindependently represent a hydrogen atom or a linear, branched, or cyclicmonovalent hydrocarbon group having 1 to 10 carbon atoms. R^(L22) andR^(L23) may bond with each other to form a ring with a carbon atombonded to R^(L22) and R^(L23). In that case, R^(L22) and R^(L23)represent a divalent group that forms a substituted or unsubstitutedcyclopentane ring or cyclohexane ring. “p” represents 1 or 2.

In the formula (L8), R^(L25) represents a linear, branched, or cyclicalkyl group having 1 to 10 carbon atoms which may be substituted, or anaryl group having 6 to 20 carbon atoms which may be substituted, andspecific examples include those the same as R^(L05).

R^(L28) represents a divalent group that forms a substituted orunsubstituted cyclopentane ring, cyclohexane ring, or norbornane ringwith a carbon atom bonded to R^(L28). R^(L26) and R^(L27) eachindependently represent a hydrogen atom or a linear, branched, or cyclicmonovalent hydrocarbon group having 1 to 10 carbon atoms. R^(L26) andR^(L27) may bond with each other to form a ring with a carbon atombonded to R^(L26) and R^(L27). In that case, R^(L26) and R^(L27)represent a divalent group that forms a substituted or unsubstitutedcyclopentane ring or cyclohexane ring. “q” represents 1 or 2.

In the formula (L9), R^(L29) represents a linear, branched, or cyclicalkyl group having 1 to 10 carbon atoms which may be substituted, or anaryl group having 6 to 20 carbon atoms which may be substituted, andspecific examples include those the same as R^(L05).

R^(L32) represents a divalent group that forms a substituted orunsubstituted cyclopentane ring, cyclohexane ring, or norbornane ringwith a carbon atom bonded to R^(L32). R^(L30) and R^(L31) eachindependently represent a hydrogen atom or a linear, branched, or cyclicmonovalent hydrocarbon group having 1 to 10 carbon atoms. R^(L30) andR^(L31) may bond with each other to form a ring with a carbon atombonded to R^(L30) and R^(L31). In that case, R^(L30) and R^(L31)represent a divalent group that forms a substituted or unsubstitutedcyclopentane ring or cyclohexane ring.

Among acid-labile groups represented by the formula (L1), specificexamples of linear or branched acid-labile groups include the followinggroups.

Among acid-labile groups represented by the formula (L1), specificexamples of cyclic acid-labile groups include a tetrahydrofuran-2-ylgroup, a 2-methyltetrahydro furan-2-yl group, a tetrahydropyran-2-ylgroup, and a 2-methyltetrahydropyran-2-yl group.

Specific examples of the acid-labile group of the formula (L2) include atert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, atert-amyloxycarbonyl group, a tert-amyloxycarbonylmethyl group, a1,1-diethylpropyloxycarbonyl group, a 1,1-diethylpropyloxycarbonylmethylgroup, a 1-ethylcyclopentyloxycarbonyl group, a1-ethylcyclopentyloxycarbonylmethyl group, a1-ethyl-2-cyclopentenyloxycarbonyl group, a1-ethyl-2-cyclopentenyloxycarbonylmethyl group, a1-ethoxyethoxycarbonylmethyl group, a2-tetrahydropyranyloxycarbonylmethyl group, and a2-tetrahydrofuranyloxycarbonylmethyl group.

Specific examples of the acid-labile group of the formula (L3) include1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl,1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl,1-tert-butylcyclopentyl, 1-cyclohexylcyclopentyl,1-(4-methoxy-n-butyl)cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl,3-methyl-1-cyclopenten-3-yl, 3-ethyl-1-cyclopenten-3-yl,3-methyl-1-cyclohexen-3-yl, and 3-ethyl-1-cyclohexen-3-yl.

As the acid-labile group of the formula (L4), groups represented by thefollowing formulae (L4-1) to (L4-4) are particularly preferable.

In the general formulae (L4-1) to (L4-4), the dotted line shows abonding position and a bonding direction. Each R^(L41) independentlyrepresents a monovalent hydrocarbon group such as a linear, branched, orcyclic alkyl group having 1 to 10 carbon atoms, and specific examplesthereof include a methyl group, an ethyl group, a propyl group, anisopropyl group, an n-butyl group, a sec-butyl group, a tert-butylgroup, a tert-amyl group, an n-pentyl group, an n-hexyl group, acyclopentyl group, and a cyclohexyl group.

In the general formulae (L4-1) to (L4-4), an enantiomer or adiastereomer can exist. The general formulae (L4-1) to (L4-4) representall of these stereoisomers. These stereoisomers may be used alone or asa mixture.

For example, the general formula (L4-3) collectively represents onegroup or a mixture of two groups selected from the groups represented bythe following general formulae (L4-3-1) and (L4-3-2).

In addition, the general formula (L4-4) collectively represents onegroup or a mixture of two or more groups selected from the groupsrepresented by the following general formulae (L4-4-1) to (L4-4-4).

The general formulae (L4-1) to (L4-4), (L4-3-1), (L4-3-2), and (L4-4-1)to (L4-4-4) also represent enantiomers thereof and a mixture of theenantiomers.

Meanwhile, a high reactivity in the acid-catalyzed elimination reactionis realized when each bonding direction of (L4-1) to (L4-4), (L4-3-1),(L4-3-2), and (L4-4-1) to (L4-4-4) points in the exo-direction of thebicyclo[2.2.1]heptane ring (see JP 2000-336121 A). In the production ofa monomer having a substituent of a tertiary exo-alkyl group that has abicyclo[2.2.1]heptane skeleton, there is a case that a monomersubstituted with the endo-alkyl group represented by the followinggeneral formulae (L4-1-endo) to (L4-4-endo) is contained. In such acase, to accomplish good reactivity, the exo-ratio is preferably 50% ormore, and the exo-ratio is further preferably 80% or more.

(See JP 2000-336121 A)

Specific examples of the acid-labile group of the formula (L4) includethe following groups.

Specific examples of the tertiary alkyl group having 4 to 20 carbonatoms, the trialkylsilyl group with each alkyl group having 1 to 6carbon atoms, and the oxoalkyl group having 4 to 20 carbon atoms includethe same substances as exemplified for R^(L04).

Specific examples of the acid-labile group of the formula (L5) include atert-butyl group, a tert-amyl group, and the following groups.

Specific examples of the acid-labile group of the formula (L6) includethe following groups.

Specific examples of the acid-labile group of the formula (L7) includethe following groups.

Specific examples of the acid-labile group of the formula (L8) includethe following groups.

Specific examples of the acid-labile group of the formula (L9) includethe following groups.

Specific examples of the monomer represented by the general formula (a1)include the following, but are not limited thereto.

(In the formula, R¹ represents a hydrogen atom or a methyl group.)

(In the formula, R¹ represents a hydrogen atom or a methyl group.)

(In the formula, R¹ represents a hydrogen atom or a methyl group.)

(In the formula, R¹ represents a hydrogen atom or a methyl group.)

Furthermore, in the base resin of the component (A), a monomer shown bythe following general formulae (a2) to (a4) is preferably used asnecessary in addition to the unit shown by the general formula (a1).

(In the formula, R¹ has the same meaning as defined above. R⁵ and R⁶each independently represent a hydrogen atom or a hydroxy group. Yrepresents a substituent having a lactone structure, or a substituenthaving a sultone structure. Z represents a hydrogen atom, a fluorinatedhydrocarbon group having 1 to 15 carbon atoms, or afluoroalcohol-containing substituent having 1 to 15 carbon atoms.)

Specific examples of the unit shown by the general formula (a2) includethe following, but are not limited thereto.

Specific examples of the monomer shown by the general formula (a3)include the following, but are not limited thereto.

(In the formula, R¹ represents a hydrogen atom or a methyl group.)

(In the formula, R¹ represents a hydrogen atom or a methyl group.)

(In the formula, R¹ represents a hydrogen atom or a methyl group.)

(In the formula, R¹ represents a hydrogen atom or a methyl group.)

Specific examples of the repeating unit shown by the general formula(a4) include the following, but are not limited thereto.

In the inventive resist composition, a monomer containing acarbon-carbon double bond other than those described above, for example,substituted acrylic esters such as methyl methacrylate, methylcrotonate, dimethyl maleate, and dimethyl itaconate, unsaturatedcarboxylic acids such as maleic acid, fumaric acid, and itaconic acid,cyclic olefins such as norbornene, norbornene derivatives, andtetracyclo[4.4.0.1^(2,5).17^(7,10)]dodecene derivatives, acid anhydridessuch as itaconic anhydride, α-methylene-γ-butyrolactones,α-methylstyrenes, and other monomers may be used.

The weight average molecular weight (Mw) of the resin A (base resin ofthe component (A)) is preferably 1,000 to 500,000, and more preferably3,000 to 100,000. With the above-described range, there is no risk ofetching resistance lowering, and resolution deteriorating due toinsufficient contrast before and after the exposure. Note that in thepresent invention, Mw is a value measured by gel permeationchromatography (GPC) in terms of polystyrene using tetrahydrofuran (THF)as an eluent.

Furthermore, in the resin A, when the molecular weight distribution(Mw/Mn) is broad, polymers having a low molecular weight and highmolecular weight are present, and therefore, there is a risk thatforeign matters are found on the pattern or that the shape of thepattern is degraded after the exposure. As a pattern rule isminiaturized, the influence of such molecular weight and molecularweight distribution is liable to increase, and therefore, the molecularweight distribution of the resin A preferably has a narrow dispersity of1.0 to 2.0, in particular, 1.0 to 1.5 to obtain a resist compositionused favorably in fine pattern dimensions.

Methods for synthesizing the resin A include a method of performing heatpolymerization on a monomer having an unsaturated bond for obtaining arepeating unit represented by the formula (a1), and if necessary,repeating units represented by the formulae (a2) to (a4) and otherrepeating units by adding a radical initiator in an organic solvent, forexample. Examples of the organic solvent used in the polymerizationinclude toluene, benzene, THF, diethyl ether, dioxane, methyl ethylketone, γ-butyrolactone, and propylene glycol monomethyl ether acetate(PGMEA). Illustrative examples of the polymerization initiator include2,2′-azobisisobutyronitrile (AIBN),2,2′-azobis(2,4-dimethylvaleronitrile), dimethyl2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide.The reaction temperature is preferably 50 to 150° C., more preferably 60to 100° C. The reaction time is preferably 2 to 24 hours. Theacid-labile group introduced into the monomer may be used as it is ormay be protected or partially protected after polymerization. Inaddition, the polymerization may be performed using a known chaintransfer agent such as dodecyl mercaptan and 2-mercaptoethanol to adjustthe molecular weight. In this case, the chain transfer agent ispreferably added in an amount of 0.01 to 10 by molar ratio in relationto all the monomers to be polymerized.

In the resin A, the preferable amount of the respective repeating unitsobtained from respective monomers may be, for example, in the rangeshown below, but is not limited thereto.

(I) a repeating unit represented by the formula (a1) is preferablycontained in an amount of 1 to 99 mol %, more preferably 20 to 95 mol %,further preferably 30 to 90 mol %, and if necessary,

(II) at least one repeating unit selected from the repeating unitsrepresented by the formulae (a2) to (a4) is preferably contained in anamount of 0 to 99 mol %, more preferably 1 to 90 mol %, and furtherpreferably 10 to 70 mol %,

(III) and other repeating units may be contained in an amount ofpreferably 0 to 99 mol %, more preferably 0 to 70 mol %, and furtherpreferably 0 to 50 mol %.

Note that the base resin of the component (A) may contain two or moreresins having different composition ratios, molecular weights, ormolecular weight distributions, and if necessary, a resin that does notcontain the repeating unit represented by the formula (a1) may becontained in addition to a resin having a repeating unit having anacid-labile group.

[(B) Photo-Acid Generator]

The inventive resist composition contains, as the component (B), aphoto-acid generator shown by the following formula (B-1),

where W₁ represents a cyclic divalent hydrocarbon group having 4 to 12carbon atoms and containing a heteroatom; W₂ represents a cyclicmonovalent hydrocarbon group having 4 to 14 carbon atoms and notcontaining a heteroatom; Rf represents a divalent organic group shown bythe above general formula; A₁ and A₂ each independently represent ahydrogen atom or a trifluoromethyl group; B₁ and B₂ each independentlyrepresent a hydrogen atom, a fluorine atom, or a trifluoromethylgroup; * represents an attachment point for a carbonyloxy group; “m”represents an integer of 0 to 4; “n” represents an integer of 0 or 1;and M⁺ represents an onium cation.

Specific examples of the cyclic divalent hydrocarbon group representedby W₁ having 4 to 12 carbon atoms and containing a heteroatom includethe following.

(* represents an attachment point for an oxycarbonyl group.)

A particularly preferable example for W₁ includes a cyclic divalenthydrocarbon group containing a lactone ring structure, and a cyclicdivalent hydrocarbon group having 6 to 12 carbon atoms and containing alactone ring structure is particularly preferable. It is possible tofurther suppress acid diffusion by having a lactone ring arranged in aposition near a sulfonic acid group at the time of acid generation afterexposure.

Specific examples of the cyclic monovalent hydrocarbon group representedby W₂ having 4 to 14 carbon atoms and not containing a heteroatominclude the following.

(The dotted line represents an attachment point.)

W₂ is preferably a polycyclic monovalent hydrocarbon group having 7 to14 carbon atoms and not containing a heteroatom. Particularly preferablegroups as W₂ include an adamantyl group. It becomes possible to providea suitable solubility by arranging a highly annelated hydrocarbon groupat the terminal.

Rf represents a divalent organic group shown by the above generalformula. Here, A₁ and A₂ each independently represent a hydrogen atom ora trifluoromethyl group; B₁ and B₂ each independently represent ahydrogen atom, a fluorine atom, or a trifluoromethyl group; and *represents an attachment point for a carbonyloxy group. “m” representsan integer of 0 to 4; and “n” represents an integer of 0 or 1.Preferably, m+n>0 holds.

In particular, the group Rf is preferably selected from groups shown bythe following formulae (Rf-1) to (Rf-6),

where * represents an attachment point for a carbonyloxy group.

The photo-acid generator shown by the formula (B-1) preferably has suchan Rf since solubility is enhanced by the effect of the fluorine atom,and a sulfonic acid that is generated after exposure comes to have asuitable acidity.

Specific examples of the structure of the anion moiety of the photo-acidgenerator shown by the formula (B-1) are shown below but are not limitedthereto.

In the formula (B-1), the onium cation represented by M⁺ is preferablyat least one cation selected from the cations shown by the followingformulae (b1) and (b2).

In the formulae (b1) and (b2), R⁴¹ to R⁴⁵ each independently represent alinear, branched, or cyclic monovalent hydrocarbon group having 1 to 20carbon atoms and optionally containing a heteroatom. In addition, anytwo out of R⁴¹, R⁴², and R⁴³ may be bonded with each other to form aring with the sulfur atom in the formula.

Examples of the monovalent hydrocarbon groups represented by R⁴¹ to R⁴⁵include alkyl groups such as a methyl group, an ethyl group, an n-propylgroup, an isopropyl group, an n-butyl group, a tert-butyl group, acyclopropyl group, a cyclopentyl group, a cyclohexyl group, acyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethylgroup, a norbornyl group, and an adamantyl group; alkenyl groups such asa vinyl group, an allyl group, a propenyl group, a butenyl group, ahexenyl group, and a cyclohexenyl group; aryl groups such as a phenylgroup, a naphthyl group, and a thienyl group; and aralkyl groups such asa benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group. Amongthese, aryl groups are preferable. Furthermore, a part of the hydrogenatoms of the monovalent hydrocarbon groups may be substituted with agroup containing a heteroatom such as an oxygen atom, a sulfur atom, anitrogen atom, and a halogen atom; and a part of the carbon atoms of themonovalent hydrocarbon groups may be substituted with a group containinga heteroatom such as an oxygen atom, a sulfur atom, and a nitrogen atom.As a result, the monovalent hydrocarbon groups may contain a hydroxygroup, a cyano group, a carbonyl group, an ether group, an ester group,a sulfonic acid ester group, a carbonate group, a lactone ring, asultone ring, a carboxylic anhydride, a haloalkyl group, etc.

Examples of the sulfonium cation represented by the formula (b1) includethose shown below, but are not limited thereto.

Examples of the iodonium cation represented by the formula (b2) includethose shown below, but are not limited thereto.

In addition, the inventive resist composition may also further contain aphoto-acid generator other than the above-described photo-acid generatorto make fine adjustments to lithography performance. As the otherphoto-acid generators, any compound that generates acid by irradiationwith a high-energy beam is possible, and a known photo-acid generatorused in conventional resist compositions, in particular, chemicallyamplified resist compositions are sufficient. Favorable photo-acidgenerators as the other photo-acid generators include a sulfonium salt,an iodonium salt, sulfonyldiazomethane, N-sulfonyloxyimide, and anoxime-o-sulfonate type acid generator. These may be used alone or as amixture of two or more kinds. As an acid generated from the otherphoto-acid generators, a strong acid such as a sulfonic acid,bis(perfluoroalkanesulfonyl)imide, andtris(perfluoromethanesulfonyl)methide, or a weak acid such as acarboxylic acid are preferable.

Specific examples of the other photo-acid generators include, forexample, the following formula (B-2), formula (B-3), and formula (B-4).

In the formula (B-2), A¹ represents a hydrogen atom or a trifluoromethylgroup. R²¹ represents a linear, branched, or cyclic monovalenthydrocarbon group having 1 to 35 carbon atoms optionally containing anoxygen atom, a nitrogen-containing heterocyclic group, or a grouprepresented by the following formula (i). M⁺ represents an onium cation.

In the formula (i), R³¹ and R³² each independently represent a hydrogenatom, or a linear, branched, or cyclic monovalent hydrocarbon grouphaving 1 to 20 carbon atoms optionally containing a heteroatom. R³¹ andR³² optionally bond with each other to form a ring with a nitrogen atombonded to R³¹ and R³². R³³ represents a linear, branched, or cyclicdivalent hydrocarbon group having 1 to 20 carbon atoms optionallycontaining a heteroatom.

Examples of the monovalent hydrocarbon group optionally containing anoxygen atom represented by R²¹ include alkyl groups such as a methylgroup, an ethyl group, a propyl group, an isopropyl group, an n-butylgroup, a sec-butyl group, a tert-butyl group, a pentyl group, a hexylgroup, a heptyl group, an octyl group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopropylmethyl group, a4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, a1-adamantyl group, and a 1-adamantylmethyl group;steroid-structure-containing groups; oxoalkyl groups such as a2-oxocyclopentyl group, a 2-oxocyclohexyl group, a 4-oxocyclohexylgroup, a 2-oxopropyl group, a 2-oxoethyl group, a2-cyclopentyl-2-oxoethyl group, a 2-cyclohexyl-2-oxoethyl group, a2-(4-methylcyclohexyl)-2-oxoethyl group, a4-oxa-tricyclo[4.2.1.0^(3,7)]nonane-5-one-9-yl group, and a4-oxo-1-adamantyl group; aryl groups including a phenyl group, a1-naphthyl group, a 2-naphthyl group, an anthranyl group, a thienylgroup, a 4-hydroxyphenyl group, alkoxyphenyl groups such as a4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group,a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, a3-tert-butoxyphenyl group, etc., alkylphenyl groups such as a2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a4-ethylphenyl group, a 4-tert-butylphenyl group, a 4-n-butylphenylgroup, a 2,4-dimethylphenyl group, etc., alkylnaphthyl groups such as amethylnaphthyl group, an ethylnaphthyl group, etc., alkoxynaphthylgroups such as a methoxynaphthyl group, ethoxynaphthyl group, etc.,dialkylnaphthyl groups such as a dimethylnaphthyl group, adiethylnaphthyl group, etc., and dialkoxynaphthyl groups such as adimethoxynaphthyl group, a diethoxynaphthyl group, etc.; aralkyl groupssuch as a benzyl group, a 1-phenylethyl group, and a 2-phenylethylgroup; and aryloxoalkyl groups such as a 2-aryl-2-oxoethyl groups suchas a 2-phenyl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a2-(2-naphthyl)-2-oxoethyl group. Other examples include a vinyl groupand an isopropenyl group.

Examples of the nitrogen-containing heterocyclic group represented byR²¹ include aziridine, pyrrolidine, piperidine, morpholine, pyrrole,pyridine, azetine, oxazole, isoxazole, thiazole, isothiazole, imidazole,pyrazole, pyridazine, pyrimidine, pyrazine, pyrroline, 2-imidazoline,imidazolidine, 3-pyrazoline, pyrazolidine, piperazine, triazine,oxadiazine, dithiazine, indole, isoindole, quinoline, isoquinoline,cinnoline, phthalazine, quinazoline, quinoxaline, 1,8-naphthyridine,purine, pteridine, indolizine, carbazole, acridine, phenazine,phenanthridine, 1,10-phenanthroline, phenoxazine, indoline, isoindoline,quinuclidine, benzo[e]indole, and benzo[cd]indole.

Particularly preferable examples of R²¹ include a tert-butyl group, acyclohexyl group, a 1-adamantyl group, a 1-adamantylmethyl group, a4-oxa-tricyclo[4.2.1.0^(3,7)]nonane-5-one-9-yl group, a4-oxo-1-adamantyl group, and a steroid-structure-containing alkyl group.

In the formula (i), examples of the monovalent hydrocarbon groupsrepresented by R³¹ and R³² include alkyl groups such as a methyl group,an ethyl group, a propyl group, an isopropyl group, an n-butyl group, asec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, aheptyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cyclopropylmethyl group, a 4-methylcyclohexylgroup, a cyclohexylmethyl group, a norbornyl group, and an adamantylgroup; alkenyl groups such as a vinyl group, an allyl group, a propenylgroup, a butenyl group, a hexenyl group, and a cyclohexenyl group; arylgroups such as a phenyl group, a naphthyl group, and a thienyl group;and aralkyl groups such as a benzyl group, a 1-phenylethyl group, and a2-phenylethyl group. Furthermore, in the hydrocarbon groups, a part ofthe hydrogen atoms of these groups may be substituted with themonovalent hydrocarbon group or a group containing a heteroatom such asan oxygen atom, a sulfur atom, a nitrogen atom, and a halogen atom; or apart of the carbon atoms of these groups may be substituted with a groupcontaining a heteroatom such as an oxygen atom, a sulfur atom, and anitrogen atom. As a result, these groups may contain a hydroxy group, acyano group, a carbonyl group, an ether group, an ester group, asulfonic acid ester group, a carbonate group, a lactone ring, a sultonering, a carboxylic anhydride, a haloalkyl group, etc.

When R³¹ and R³² bond with each other to form a ring with a nitrogenatom bonded to R³¹ and R³², specific examples of rings includeaziridine, pyrrolidine, piperidine, morpholine, pyrrole, pyridine,azetine, oxazole, isoxazole, thiazole, isothiazole, imidazole, pyrazole,pyridazine, pyrimidine, pyrazine, pyrroline, 2-imidazoline,imidazolidine, 3-pyrazoline, pyrazolidine, piperazine, triazine,oxadiazine, dithiazine, indole, isoindole, quinoline, isoquinoline,cinnoline, phthalazine, quinazoline, quinoxaline, 1,8-naphthyridine,purine, pteridine, indolizine, carbazole, acridine, phenazine,phenanthridine, 1,10-phenanthroline, phenoxazine, indoline, isoindoline,quinuclidine, benzo[e]indole, and benzo[cd]indole. In addition, a partof the hydrogen atoms of these rings may be substituted with theabove-described hydrocarbon group or a group containing a heteroatomsuch as an oxygen atom, a sulfur atom, a nitrogen atom, and a halogenatom; or a part of the carbon atoms of these rings may be substitutedwith a group containing a heteroatom such as an oxygen atom, a sulfuratom, and a nitrogen atom. As a result, these groups may contain ahydroxy group, a cyano group, a carbonyl group, an ether group, an estergroup, a sulfonic acid ester group, a carbonate group, a lactone ring, asultone ring, a carboxylic anhydride, a haloalkyl group, etc.

In the formula (i), examples of the divalent hydrocarbon grouprepresented by R³³ include linear alkanediyl groups such as a methylenegroup, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diylgroup, a pentane-1,5-diyl group, a hexane-1,6-diyl group, aheptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diylgroup, a decane-1,10-diyl group, an undecane-1,11-diyl group, adodecane-1,12-diyl group, a tridecane-1,13-diyl group, atetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, ahexadecane-1,16-diyl group, and a heptadecane-1,17-diyl group; branchedalkanediyl groups with a side chain of a methyl group, an ethyl group, apropyl group, an isopropyl group, a butyl group, a sec-butyl group, atert-butyl group, etc. added to the linear alkanediyl groups; saturatedcyclic hydrocarbon groups such as a cyclopentanediyl group, acyclohexanediyl group, a norbornanediyl group, and an adamantanediylgroup; and unsaturated cyclic divalent hydrocarbon groups such as aphenylene group and a naphthylene group. In addition, a part of hydrogenatoms of these groups may be substituted with a group containing aheteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, and ahalogen atom; or a part of the carbon atoms of these groups may beinterposed by a group containing a heteroatom such as an oxygen atom, asulfur atom, and a nitrogen atom. As a result, these groups may containa hydroxy group, a cyano group, a carbonyl group, an ether group, anester group, a sulfonic acid ester group, a carbonate group, a lactonering, a sultone ring, a carboxylic anhydride, a haloalkyl group, etc.

Specific examples of the structure of the anion moiety of the photo-acidgenerator shown by the formula (B-2) are shown below but are not limitedthereto. Note that in the following formulae, A¹ has the same meaning asdefined above.

In the formula (B-2), the onium cation represented by M⁺ is preferablyat least one cation selected from the cations shown by the formulae (b1)and (b2).

In the formula (B-3), A² represents a hydrogen atom or a trifluoromethylgroup. R²², R²³, and R²⁴ each independently represent a hydrogen atom ora linear, branched, or cyclic monovalent hydrocarbon group having 1 to20 carbon atoms optionally containing a heteroatom. “p” and “q” eachindependently represent an integer of 0 to 5. “r” represents an integerof 0 to 4. L represents a single bond, an ether group, or a linear,branched, or cyclic divalent hydrocarbon group having 1 to 20 carbonatoms optionally containing a heteroatom.

Examples of the monovalent hydrocarbon group represented by R²², R²³,and R²⁴ include alkyl groups such as a methyl group, an ethyl group, apropyl group, an isopropyl group, an n-butyl group, a sec-butyl group, atert-butyl group, a tert-pentyl group, an n-pentyl group, an n-hexylgroup, an n-octyl group, an n-nonyl group, an n-decyl group, acyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, acyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutylgroup, a cyclohexylmethyl group, a cyclohexylethyl group, acyclohexylbutyl group, a norbornyl group, an oxanorbornyl group, atricyclo[5.2.1.0^(2,6)]decanyl group, and an adamantyl group. Inaddition, a part of hydrogen atoms of these groups may be substitutedwith a group containing a heteroatom such as an oxygen atom, a sulfuratom, a nitrogen atom, and a halogen atom; or a part of the carbon atomsof these groups may be substituted with a group containing a heteroatomsuch as an oxygen atom, a sulfur atom, and a nitrogen atom. As a result,these groups may contain a hydroxy group, a cyano group, a carbonylgroup, an ether group, an ester group, a sulfonic acid ester group, acarbonate group, a lactone ring, a sultone ring, a carboxylic anhydride,a haloalkyl group, etc. A methyl group, a methoxy group, a tert-butylgroup, a tert-butoxy group, etc. are preferable as R²², R²³ and R²⁴.

In the formula (B-3), examples of the divalent hydrocarbon grouprepresented by L include the same groups as those exemplified as R³³,and furthermore, a combination of two or more of these groups is alsopossible. In addition, a part of hydrogen atoms of these groups may besubstituted with a group containing a heteroatom such as an oxygen atom,a sulfur atom, a nitrogen atom, and a halogen atom; or a part of thecarbon atoms of these groups may be substituted with a group containinga heteroatom such as an oxygen atom, a sulfur atom, and a nitrogen atom.As a result, these groups may contain a hydroxy group, a cyano group, acarbonyl group, an ether group, an ester group, a sulfonic acid estergroup, a carbonate group, a lactone ring, a sultone ring, a carboxylicanhydride, a haloalkyl group, etc.

Examples of the photo-acid generator shown by the formula (B-3) includethose shown below, but are not limited thereto. Note that in thefollowing formulae, A² has the same meaning as defined above.

(B) the photo-acid generator may further contain a compound shown by theformula (B-4). In the formula (B-4), A³ and A⁴ each independentlyrepresent a hydrogen atom or a trifluoromethyl group, and are not both ahydrogen atom at the same time. R²⁵ represents a linear, branched, orcyclic monovalent hydrocarbon group having 1 to 35 carbon atomsoptionally containing an oxygen atom, a nitrogen-containing heterocyclicgroup, or a group shown by the formula (i). M⁺ is the same as theabove-mentioned onium cation.

Specific examples of the structure of the anion moiety of the photo-acidgenerator shown by the formula (B-4) are shown below but are not limitedthereto.

Among the above-described other photo-acid generators, the compoundshaving a fluorine-atom-containing structure including a trifluoromethylgroup in the anion structure portion each have a high hydrophobicity,and little elution to immersion liquid. In addition, since the compoundshave a fluorine-atom-containing structure, solvent solubility is high,and it becomes possible to reduce the residue after development inorganic solvent development. In this manner, defects after developmentcan be reduced, and this is suitable for a resist composition for ArFimmersion exposure.

Specific examples other than the above-described photo-acid generatorsinclude, for example, the compounds disclosed in paragraphs [0122] to[0142] of JP 2008-111103 A, and particularly preferable examples includethe compounds disclosed in paragraphs [0088] to [0092] of JP 2014-001259A, the compounds disclosed in paragraphs [0015] to [0017] of JP2012-41320 A, and compounds disclosed in paragraphs [0015] to [0029] ofJP 2012-106986 A. The partially fluorinated sulfonic-acid-generatingphoto-acid generators disclosed in the patent documents have suitablestrength and diffusion length of the generated acid, particularly in ArFlithography, and may be used favorably.

The photo-acid generator of the component (B) is preferably contained inan amount of 0.1 to 50 parts by mass, more preferably 0.2 to 40 parts bymass, and further preferably 0.3 to 35 parts by mass based on 100 partsby mass of the base resin of the component (A). Within the above ranges,resolution is not degraded, and there is no risk of problems of foreignmatters occurring after development of or when delaminating a resistfilm. Note that when a compound shown by the formula (B-4) is added, thecontent amount is preferably 0 to 50 mass % of the photo-acid generatorof the component (B).

[(C) Solvent]

The inventive resist composition contains a solvent as the component(C). Examples of the solvent include those disclosed in paragraphs[0144] to [0145] of JP 2008-111103 A: ketones such as cyclohexanone andmethyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol,3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether,ethylene glycol monomethyl ether, propylene glycol monoethyl ether,ethylene glycol monoethyl ether, propylene glycol dimethyl ether, anddiethylene glycol dimethyl ether; esters such as PGMEA, propylene glycolmonoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate,methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butylacetate, tert-butyl propionate, and propylene glycol mono-tert-butylether acetate; lactones such as γ-butyrolactone; keto-alcohols such asdiacetone alcohol; and mixed solvents thereof. When an acetal-basedacid-labile group is used, a high-boiling-point alcohol-based solvent,specifically, diethylene glycol, propylene glycol, glycerin,1,4-butanediol, 1,3-butanediol, etc., may be added in order toaccelerate deprotection reaction of the acetal.

The solvent of the component (C) is preferably contained in an amount of100 to 10,000 parts by mass, more preferably 300 to 8,000 parts by massbased on 100 parts by mass of the base resin of the component (A).

[(D) Fluorine-Containing Resin]

The inventive resist composition may contain a resin being afluorine-containing resin containing at least one repeating unitselected from repeating units shown by the following formulae (D-1),(D-2), and (D-3), where the resin is different from the resin A.

In the formula, R^(A) represents a hydrogen atom or a methyl group. R⁵¹and R⁵² each independently represent a hydrogen atom or a linear,branched, or cyclic monovalent hydrocarbon group having 1 to 10 carbonatoms. R⁵³ represents a single bond or a linear or branched divalenthydrocarbon group having 1 to 5 carbon atoms. R⁵⁴, R⁵⁵, and R⁵⁶ eachindependently represent a hydrogen atom, a linear, branched, or cyclicmonovalent hydrocarbon group, fluorinated monovalent hydrocarbon group,or acyl group having 1 to 15 carbon atoms, or an acid-labile group. WhenR⁵⁴, R⁵⁵, and R⁵⁶ represent the monovalent hydrocarbon group or thefluorinated monovalent hydrocarbon group, some carbon atoms thereof areoptionally substituted with an ether group or a carbonyl group. R⁵⁷represents a linear, branched, or cyclic hydrocarbon group orfluorinated hydrocarbon group with a valency of (v+1) having 1 to 20carbon atoms. “v” represents an integer of 1 to 3.

Examples of the monovalent hydrocarbon groups having 1 to 10 carbonatoms represented by R⁵¹ and R⁵² include alkyl groups such as a methylgroup, an ethyl group, an n-propyl group, an isopropyl group, acyclopropyl group, an n-butyl group, an isobutyl group, a sec-butylgroup, a tert-butyl group, a cyclobutyl group, an n-pentyl group, acyclopentyl group, an n-hexyl group, a cyclohexyl group, an n-heptylgroup, an n-octyl group, an n-nonyl group, an n-decyl group, anadamantyl group, and a norbornyl group. Among these groups, a linear,branched, or cyclic monovalent hydrocarbon group having 1 to 6 carbonatoms is preferable.

Specific examples of the divalent hydrocarbon group having 1 to 5 carbonatoms represented by R⁵³ include a methylene group, an ethylene group, atrimethylene group, a propylene group, a tetramethylene group, and apentamethylene group.

Examples of the monovalent hydrocarbon groups having 1 to 15 carbonatoms represented by R⁵⁴, R⁵⁵, and R⁵⁶ include an alkyl group, analkenyl group, and an alkynyl group, and an alkyl group is preferable.Other than those described above, examples of the alkyl group include ann-undecyl group, an n-dodecyl group, a tridecyl group, a tetradecylgroup, and a pentadecyl group. Examples of the fluorinated monovalenthydrocarbon group having 1 to 15 carbon atoms include groups having someor all of the hydrogen atoms bonded to the carbon atoms of theabove-described monovalent hydrocarbon groups substituted with afluorine atom. As stated above, a part of these carbon atoms may besubstituted with an ether group or a carbonyl group.

When R⁵⁴, R⁵⁵, and R⁵⁶ represent acid-labile groups, specific examplesthereof include groups shown by the above-described formulae (L1) to(L9), a tertiary alkyl group having 4 to 20, preferably 4 to 15 carbonatoms, a trialkylsilyl group with each alkyl group having 1 to 6 carbonatoms, and an oxoalkyl group having 4 to 20 carbon atoms.

Examples of the hydrocarbon group or fluorinated hydrocarbon group witha valency of (v+1) having 1 to 20 carbon atoms represented by R⁵⁷include groups further having a required number of hydrogen atomsremoved from the above-described monovalent hydrocarbon group orfluorinated monovalent hydrocarbon group, etc.

Examples of the repeating unit shown by the formula (D-1) include thoseshown below, but are not limited thereto. Note that in the followingformulae, R^(A) has the same meaning as defined above.

Examples of the repeating unit shown by the formula (D-2) include thoseshown below, but are not limited thereto. Note that in the followingformulae R^(A) has the same meaning as defined above.

Examples of the repeating unit shown by the formula (D-3) include thoseshown below, but are not limited thereto. Note that in the followingformulae, R^(A) has the same meaning as defined above.

The Mw of the fluorine-containing resin of the component (D) ispreferably 1,000 to 100,000, more preferably 3,000 to 15,000. Mw/Mn ispreferably 1.0 to 2.0, more preferably 1.0 to 1.6.

To synthesize the fluorine-containing resin of the component (D) onemethod is to perform heat polymerization on a monomer having anunsaturated bond for obtaining a repeating unit represented by theformulae (D-1) to (D-3) and other repeating units as necessary by addinga radical initiator in an organic solvent. Examples of the organicsolvent used in the polymerization include toluene, benzene, THF,diethyl ether, dioxane, methyl ethyl ketone, propylene glycol monomethylether, and propylene glycol monomethyl ether acetate. Examples of thepolymerization initiator include AIBN,2,2′-azobis(2,4-dimethylvaleronitrile), dimethyl2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide.The reaction temperature is preferably 50 to 100° C. The reaction timeis preferably 4 to 24 hours. As the acid-labile group, the acid-labilegroup introduced into the monomer may be used as it is or may beprotected or partially protected after polymerization. In addition, thepolymerization may be performed using known chain transfer agents suchas dodecyl mercaptan and 2-mercaptoethanol to adjust the molecularweight. In this case, the chain transfer agent is preferably added in anamount of 0.01 to 10 by molar ratio in relation to all the monomers tobe polymerized.

When the inventive resist composition contains a fluorine-containingresin of the component (D), the content amount thereof is preferably 0.1to 50 parts by mass, more preferably 0.5 to 10 parts by mass based on100 parts by mass of the base resin of the component (A). When thecontent amount is within the above range, the contact angle between aresist film surface and water increases sufficiently, and defects due toremaining immersion liquid and elution of an acid generator or aquencher can be suppressed. Furthermore, it becomes possible to adjustthe solubility of the resist film surface, and a favorable criticaldimension uniformity can be achieved.

[Other Components]

The inventive resist composition may contain an amine compound, asulfonic acid salt, or a carboxylic acid salt as a quencher asnecessary. Herein, the quencher means a compound that can suppressdiffusion rate when an acid generated from the photo-acid generator isdiffused into a resist film.

Among such quenchers, examples of the amine compound include primary,secondary, or tertiary amine compounds disclosed in paragraphs [0146] to[0164] of JP 2008-111103 A, and particularly preferable examples includeamine compounds having any of a hydroxy group, an ether group, an estergroup, a lactone ring, a cyano group, or a sulfonic acid ester group.Other examples include a compound having a primary or secondary amineprotected by forming a carbamate group as disclosed in Japanese PatentNo. 3790649. A protected amine compound as described is effective whenthere is a component that is unstable to a base in the resistcomposition.

Examples of the sulfonic acid salt include compounds shown by thefollowing formula (Z1). Meanwhile, examples of the carboxylic acid saltinclude compounds shown by the following formula (Z2).R¹⁰¹—SO₃ ⁻M⁺  (Z1)R¹⁰²—CO₂ ⁻M⁺  (Z2)

R¹⁰¹ represents a hydrogen atom or a hydrocarbyl group having 1 to 40carbon atoms optionally containing a heteroatom, but excluding groupshaving a hydrogen atom bonded to a carbon atom in an α position of asulfo group in which the hydrogen atom is substituted with a fluorineatom or a fluoroalkyl group. M⁺ each independently represents an oniumcation, and examples include those exemplified above.

The hydrocarbyl group may be saturated or unsaturated, and may be any oflinear, branched, or cyclic. Specific examples thereof include alkylgroups such as a methyl group, an ethyl group, a propyl group, anisopropyl group, an n-butyl group, a sec-butyl group, a tert-butylgroup, a tert-pentyl group, an n-pentyl group, an n-hexyl group, ann-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decylgroup; cyclic saturated hydrocarbyl groups such as a cyclopentyl group,a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group,a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethylgroup, a cyclohexylbutyl group, a norbornyl group, atricyclo[5.2.1.0^(2,6)]decanyl group, an adamantyl group, and anadamantylmethyl group; alkenyl groups such as a vinyl group, an allylgroup, a propenyl group, a butenyl group, and a hexenyl group;unsaturated aliphatic cyclic hydrocarbyl groups such as a cyclohexenylgroup; aryl groups such as a phenyl group, a naphthyl group, alkylphenylgroups (a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenylgroup, a 4-ethylphenyl group, a 4-tert-butylphenyl group, a4-n-butylphenyl group, etc.), dialkylphenyl groups (a 2,4-dimethylphenylgroup, a 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl groups (amethylnaphthyl group, an ethylnaphthyl group, etc.), and dialkylnaphthylgroups (a dimethylnaphthyl group, a diethylnaphthyl group, etc.);heteroaryl groups such as a thienyl group; and aralkyl groups such as abenzyl group, a 1-phenylethyl group, and a 2-phenylethyl group.

In addition, a part of hydrogen atoms of these groups may be substitutedwith a group containing a heteroatom such as an oxygen atom, a sulfuratom, a nitrogen atom, and a halogen atom, and a part of the carbonatoms of these groups may be substituted with a group containing aheteroatom such as an oxygen atom, a sulfur atom, and a nitrogen atom.As a result, these groups may contain a hydroxy group, a cyano group, acarbonyl group, an ether bond, an ester bond, a sulfonic acid esterbond, a carbonate bond, a lactone ring, a sultone ring, a carboxylicanhydride, a haloalkyl group, etc. Examples of the hydrocarbyl groupcontaining a heteroatom include alkoxyphenyl groups such as a4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group,a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenylgroup, and a 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as amethoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthylgroup, and an n-butoxynaphthyl group; dialkoxynaphthyl groups such as adimethoxynaphthyl group, and a diethoxynaphthyl group; and aryloxoalkylgroups such as 2-aryl-2-oxoethyl groups, for example, a2-phenyl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a2-(2-naphthyl)-2-oxoethyl group.

R¹⁰² represents a hydrocarbyl group having 1 to 40 carbon atomsoptionally containing a heteroatom. Examples of the hydrocarbyl grouprepresented by R¹⁰² include those exemplified as the hydrocarbyl grouprepresented by R¹⁰¹. In addition, other specific examples includefluorine-containing alkyl groups such as a trifluoromethyl group, atrifluoroethyl group, a 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group,and a 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group; andfluorine-containing aryl groups such as a pentafluorophenyl group and a4-trifluoromethylphenyl group.

Examples of the sulfonic acid salt represented by the formula (Z1)include those shown below, but are not limited thereto.

Examples of the carboxylic acid salt shown by the formula (Z2) includethose shown below, but are not limited thereto.

When the inventive resist composition contains the quencher, the contentamount thereof is preferably 0.001 to 12 parts by mass, more preferably0.01 to 8 parts by mass based on 100 parts by mass of the base resin ofthe component (A). By blending the quencher, not only resist sensitivitycan be readily adjusted, but also diffusion rate of acids in the resistfilm is suppressed to improve resolution and suppress change insensitivity after exposure, or reducing dependence on a substrate or anenvironment enables to improve an exposure margin, a pattern profile,etc. In addition, by adding these quenchers, substrate adhesiveness canalso be improved. The quenchers may be used alone or as a combination oftwo or more kinds.

[Surfactant]

The inventive resist composition may contain a component of a surfactantinsoluble or hardly soluble in water and soluble in alkaline developer,and/or a surfactant insoluble or hardly soluble in water and alkalinedeveloper. As such a surfactant, the component defined in (S) disclosedin JP 2010-215608 A and JP 2011-16746 A may be referred to.

As the surfactant insoluble or hardly soluble in water and alkalinedeveloper, among the surfactants disclosed in the above patentdocuments, FC-4430 (manufactured by 3M), Surflon (Registered Trademark)5-381 (manufactured by AGC SEIMI CHEMICAL CO., LTD.), Surfynol(Registered Trademark) E1004 (manufactured by Air Products Limited),KH-20, KH-30 (manufactured by ASAHI GLASS CO., LTD.), and oxetanering-opened polymers represented by the following structural formula(surf-1) are preferable. These may be used alone or in combination oftwo or more.

Here, Rf, R, M, A, B, C, and N in the above formula are applied only tothis formula.

In the formula (surf-1), R represents a 2- to 4-valent aliphatic grouphaving 2 to 5 carbon atoms, and specific examples of the divalent groupinclude an ethylene group, a tetramethylene group, a propylene group, a2,2-dimethyl-1,3-propanediyl group, and a pentamethylene group, andexamples of the trivalent or tetravalent group include those shownbelow.

In the formula, the dotted line represents an attachment point, andthese are partial structures derived from glycerol, trimethylolethane,trimethylolpropane, and pentaerythritol, respectively.

Among these, a tetramethylene group or a 2,2-dimethyl-1,3-propanediylgroup is preferably used. Rf represents a trifluoromethyl group or apentafluoroethyl group, preferably a trifluoromethyl group. M representsan integer of 0 to 3, N represents an integer of 1 to 4, and the sum ofM and N represents a number of valence of R, and is an integer of 2 to4. A represents 1, B represents an integer of 2 to 25, and C representsan integer of 0 to 10. B preferably represents an integer of 4 to 20,and C preferably represents 0 or 1. In addition, the above structuredoes not specify the arrangement of the respective constitutional units,and the units may be bonded as a block or randomly. The production ofthe surfactant with the type of a partially fluorinated oxetanering-opened polymer is described in detail in U.S. Pat. No. 5,650,483,etc.

[Patterning Process]

The present invention further provides a patterning process using theabove-described resist composition. To form a pattern using theinventive resist composition, a known lithography technique may beadopted. Specifically, for example, a substrate for manufacturing anintegrated circuit (Si, SiO₂, SiN, SiON, TiN, WSi, BPSG, SOG, an organicantireflection film, etc.), or a substrate for manufacturing a maskcircuit (Cr, CrO, CrON, MoSi₂, SiO₂, etc.) is coated with the inventiveresist composition by a procedure such as spin coating so as to give afilm thickness of 0.05 to 2 μm, and then prebaked on a hot platepreferably at 60 to 150° C., for 1 to 10 minutes, more preferably at 80to 140° C. for 1 to 5 minutes to form a resist film.

Next, a mask for forming a desired pattern is then placed over theresist film, and the resist film is irradiated with a high-energy beamsuch as a KrF excimer laser, an ArF excimer laser, EUV having awavelength of 3 to 15 nm and EB (electron beam) with the exposure dosepreferably 1 to 200 mJ/cm², more preferably 10 to 100 mJ/cm², orpreferably 0.1 to 100 μC/cm², more preferably 0.5 to 50 μC/cm². In theexposure, the general exposure method can be used, and besides this, theimmersion method conducted by placing a liquid having a refractive indexof 1.0 or more between a resist film and a projection lens can be used.In this case, a protective film insoluble in water may be used.Subsequently, post-exposure bake (PEB) may be carried out on a hot platepreferably at 60 to 150° C. for 1 to 5 minutes, more preferably at 80 to140° C. for 1 to 3 minutes. Thereafter, development is carried out byusing a developer composed of an aqueous alkali solution such as atetramethylammonium hydroxide (TMAH) solution with a concentration ofpreferably 0.1 to 5 mass %, more preferably 2 to 3 mass %, or an organicsolvent developer such as a butyl acetate, in a conventional manner suchas dip, puddle, or spray method preferably for 0.1 to 3 minutes, morepreferably 0.5 to 2 minutes to form the desired pattern on thesubstrate.

The protective film insoluble in water serves to prevent a substanceeluted from the resist film and increase water-sliding property of thefilm surface. The protective film is largely classified into two kinds.One is an organic solvent-removing protective film, which needs to beremoved before alkaline development by an organic solvent that does notdissolve the resist film. The other is an alkali-soluble protectivefilm, which is soluble in an alkaline developer and is removed togetherwith the soluble part of the resist film. The latter protective film ispreferably obtained from a material which contains a base polymercompound having a 1,1,1,3,3,3-hexafluoro-2-propanol residue in which thepolymer is insoluble in water and soluble in an alkaline developer, anddissolved in an alcohol solvent having 4 or more carbon atoms, an ethersolvent having 8 to 12 carbon atoms, or a mixed solvent thereof. Theabove-described surfactant insoluble in water and soluble in an alkalinedeveloper may be dissolved in an alcohol solvent having 4 or more carbonatoms, an ether solvent having 8 to 12 carbon atoms, or a mixed solventthereof to prepare a material for the alkali-soluble protective film.

In addition, as a means of the patterning process, after a photoresistfilm is formed, acid generators, etc. may be extracted from the surfaceof the film, or particles may be washed off, by rinsing with pure water(post-soak). Alternatively, after exposure, remaining water on the filmmay be removed by rinsing (post-soak).

Note that, an aqueous alkaline solution such as TMAH with aconcentration of preferably 0.1 to 5 mass %, more preferably 2 to 3 mass% can be used as the developer for the inventive patterning process asdescribed above, and an organic solvent can also be used. In this case,a negative tone development, which develops/dissolves the unexposed partmay be performed.

For the organic solvent development, one or more developer selected from2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone,2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone,acetophenone, methylacetophenone, propyl acetate, butyl acetate,isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate,phenyl acetate, propyl formate, butyl formate, isobutyl formate, pentylformate, isopentyl formate, methyl valerate, methyl pentenoate, methylcrotonate, ethyl crotonate, methyl lactate, ethyl lactate, propyllactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyllactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methylbenzoate, ethyl benzoate, benzyl acetate, methyl phenylacetate, benzylformate, phenylethyl formate, methyl 3-phenylpropionate, benzylpropionate, ethyl phenylacetate, and 2-phenylethyl acetate may be used.

EXAMPLE

Hereinafter, the present invention will be described specifically withreference to Examples and Comparative Examples, but the presentinvention is not limited to the following Examples.

[1] Synthesis of Onium Salt

[Example 1-1] Synthesis of PAG-1

PAG-1 was synthesized according to the following scheme.

After mixing 100 g of an ammonium salt 1, 68.7 g of a cationintermediate 1, 100 g of pure water, and 400 g of methylene chloride,the resultant was stirred and aged for 1 hour. After isolating theorganic layer, the resultant was washed twice with a mixed solution of5.7 g of the cation intermediate 1 and 100 g of pure water, five timeswith 100 g of pure water, and twice with 100 g of a 20 wt % aqueousmethanol solution. The obtained organic layer was concentrated, PGMEAwas added thereto and concentration was performed again to obtain a 20wt % PGMEA solution. The obtained PGMEA solution was stirred all nightat room temperature to deposit a solid, then 500 g of hexane was furtheradded thereto and stirred for 2 hours. The obtained solid was collectedby filtration, rinsed with 200 g of hexane, and finally dried by heatingunder reduced pressure at 50° C. to obtain 104.8 g (yield: 88%) of thedesired PAG 1. ¹HNMR of the obtained PAG 1 is shown in FIG. 1 , and¹⁹FNMR of the obtained PAG 1 is shown in FIG. 2 .

IR (D-ATR): ν=3087, 3002, 2906, 2852, 1785, 1727, 1477, 1448, 1344,1240, 1180, 1103, 1076, 1035, 1010, 997, 943, 750, 684, 642, 551, 522,501 cm⁻¹

[Examples 1-2 to 1-8] Synthesis of Other PAGs (PAG-2 to PAG-8)

Using corresponding ingredients, PAG-2 to PAG-8 were synthesized by aknown organic synthesis method.

[2] Synthesis of Polymer

The polymer used in the inventive resist composition was synthesized bythe method described below. Note that the Mw of the obtained polymer wasmeasured by GPC in terms of polystyrene using THF as an eluent.

[Synthesis Example 1] Synthesis of Resist Polymer 1

Under a nitrogen atmosphere, α-methacryloxy-γ-butyrolactone (32.5 g),3-hydroxyadamantyl methacrylate (12.9 g), 1-ethylcyclopentylmethacrylate (54.6 g), and dimethyl 2,2′-azobisisobutyrate (6.27 g) weredissolved in PGMEA (155 g) to prepare a solution. Under a nitrogenatmosphere, the solution was dropped in over 5 hours to PGMEA (78 g)stirred at 80° C. After the dropping was completed, the resultant wasstirred for 2 hours while maintaining at 80° C., was cooled to roomtemperature, and then the reaction solution was dropped into methanol(2000 g). The deposited solid was collected by filtration, dried undervacuum at 50° C. for 20 hours, and a resist polymer 1 was obtained as awhite powder solid. The yield was 82 g and 82%.

[Synthesis Examples 2 to 5] Synthesis of Resist Polymers 2 to 5

The following resist polymers 2 to 5 were manufactured by the samemethod as in Synthesis Example 1 except that the kind of monomer andblending ratio were changed.

[3] Preparation of Resist Composition

Examples 2-1 to 2-35 and Comparative Examples 1-1 to 1-28

The onium salts of the present invention (PAG-1 to PAG-8), comparativephoto-acid generators PAG-A to PAG-H, resist polymers 1 to 5, otherphoto-acid generators PAG-X to PAG-Z, quenchers Q-1 to Q-4, and analkali-soluble surfactant SF-1 were dissolved in a solvent containing0.01 mass % of a surfactant A (available from Omnova Solutions, Inc.) bythe composition shown in the following Table 1 to prepare a solution.The solution was filtered through a 0.2 μm filter made of Teflon(Registered Trademark) to prepare resist compositions.

TABLE 1 Fluo- Other Other rine- Acid Acid Acid Acid con- gener- gener-gener- gener- taining Solvent Solvent ator 1 ator 2 ator 1 ator 2polymer 1 2 Com- Base resin (parts (parts (parts (parts Quencher (parts(parts (parts posi- (parts by by by by by (parts by by by tion mass)mass) mass) mass) mass) by mass) mass) mass) mass) Example 2-1 R-1 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 1(5) (1,380)(220) Example 2-2 R-2  Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2polymer 1(80) 2(5) (1,380) (220) Example 2-3 R-3  Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 3(5) (1,380) (220) Example 2-4R-4  Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 4(5)(1,380) (220) Example 2-5 R-5  Resist PAG- — — — Q-1(2)   SF-1(5) S-1S-2 polymer 1(80) 5(5) (1,380) (220) Example 2-6 R-6  Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 6(5) (1,380) (220) Example 2-7R-7  Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 7(5)(1,380) (220) Example 2-8 R-8  Resist PAG- — — — Q-1(2)   SF-1(5) S-1S-2 polymer 1(80) 8(5) (1,380) (220) Example 2-9 R-9  Resist PAG- PAG- —— Q-1(2)   SF-1(3) S-1 S-2 polymer 1(80) 1(3) 2(2) (1,380) (220) Example2-10 R-10 Resist PAG- PAG- — — Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80)1(3) 3(2) (1,380) (220) Example 2-11 R-11 Resist PAG- PAG- — — Q-1(2)  SF-1(5) S-1 S-2 polymer 1(80) 1(3) 4(2) (1,380) (220) Example 2-12 R-12Resist PAG- — PAG- — Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 1(3) X(3)(1,380) (220) Example 2-13 R-13 Resist PAG- — PAG- — Q-1(2)   SF-1(5)S-1 S-2 polymer 1(80) 1(3) Y(3) (1,380) (220) Example 2-14 R-14 ResistPAG- — PAG- — Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 1(3) Z(3) (1,380)(220) Example 2-15 R-15 Resist PAG- — PAG- PAG- Q-1(2)   SF-1(5) S-1 S-2polymer 1(80) 1(3) X(2) Y(2) (1,380) (220) Example 2-16 R-16 Resist PAG-— PAG- PAG- Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 1(3) Y(2) Z(2)(1,380) (220) Example 2-17 R-17 Resist PAG- — — — Q-2(2)   SF-1(5) S-1S-2 polymer 1(80) 1(5) (1,380) (220) Example 2-18 R-18 Resist PAG- — — —Q-3(1)   SF-1(5) S-1 S-2 polymer 1(80) 1(5) (1,380) (220) Example 2-19R-19 Resist PAG- — — — Q-4(1.5) SF-1(5) S-1 S-2 polymer 1(80) 1(5)(1,380) (220) Example 2-20 R-20 Resist PAG- — — — Q-1(2)   SF-1(5) S-1S-2 polymer 2(80) 1(5) (1,380) (220) Example 2-21 R-21 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 polymer 3(80) 1(5) (1,380) (220) Example 2-22R-22 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 polymer 1(80) 1(5)(1,380) (220) Example 2-23 R-23 Resist PAG- — — — Q-1(5)   SF-1(5) S-1S-2 polymer 1(80) 1(10) (1,380) (220) Example 2-24 R-24 Resist PAG- — —— Q-1(7)   SF-1(5) S-1 S-2 polymer 1(80) 1(20) (1,380) (220) Example2-25 R-25 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 polymer 4(80) 1(5)(1,380) (220) Example 2-26 R-26 Resist PAG- — — — Q-1(2)   SF-1(5) S-1S-2 polymer 4(80) 2(5) (1,380) (220) Example 2-27 R-27 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 polymer 4(80) 3(5) (1,380) (220) Example 2-28R-28 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 polymer 4(80) 4(5)(1,380) (220) Example 2-29 R-29 Resist PAG- — — — Q-1(2)   SF-1(5) S-1S-2 polymer 4(80) 5(5) (1,380) (220) Example 2-30 R-30 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 polymer 4(80) 6(5) (1,380) (220) Example 2-31R-31 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 polymer 4(80) 7(5)(1,380) (220) Example 2-32 R-32 Resist PAG- — — — Q-1(2)   SF-1(5) S-1S-2 polymer 4(80) 8(5) (1,380) (220) Example 2-33 R-33 Resist PAG- —PAG- — Q-1(2)   SF-1(5) S-1 S-2 polymer 5(80) 1(3) X(3) (1,380) (220)Example 2-34 R-34 Resist PAG- — PAG- — Q-1(2)   SF-1(5) S-1 S-2 polymer5(80) 1(3) Y(3) (1,380) (220) Example 2-35 R-35 Resist PAG- — PAG- —Q-1(2)   SF-1(5) S-1 S-2 polymer 5(80) 1(3) Z(3) (1,380) (220)Comparative R-36 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-1polymer 1(80) A(5) (1,380) (220) Comparative R-37 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-2 polymer 1(80) B(5) (1,380) (220)Comparative R-38 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-3polymer 1(80) C(5) (1,380) (220) Comparative R-39 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-4 polymer 1(80) D(5) (1,380) (220)Comparative R-40 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-5polymer 1(80) E(5) (1,380) (220) Comparative R-41 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-6 polymer 1(80) E(5) (1,380) (220)Comparative R-42 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-7polymer 1(80) G(5) (1,380) (220) Comparative R-43 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-8 polymer 1(80) H(5) (1,380) (220)Comparative R-44 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-9polymer 2(80) A(5) (1,380) (220) Comparative R-45 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-10 polymer 2(80) B(5) (1,380) (220)Comparative R-46 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-11polymer 2(80) C(5) (1,380) (220) Comparative R-47 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-12 polymer 2(80) D(5) (1,380) (220)Comparative R-48 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-13polymer 2(80) E(5) (1,380) (220) Comparative R-49 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-14 polymer 3(80) A(5) (1,380) (220)Comparative R-50 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-15polymer 3(80) B(5) (1,380) (220) Comparative R-51 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-16 polymer 3(80) C(5) (1,380) (220)Comparative R-52 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-17polymer 3(80) D(5) (1,380) (220) Comparative R-53 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-18 polymer 3(80) E(5) (1,380) (220)Comparative R-54 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-19polymer 4(80) A(5) (1,380) (220) Comparative R-55 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-20 polymer 4(80) B(5) (1,380) (220)Comparative R-56 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-21polymer 4(80) C(5) (1,380) (220) Comparative R-57 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-22 polymer 4(80) D(5 (1,380) (220)Comparative R-58 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-23polymer 4(80) E(5) (1,380) (220) Comparative R-59 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-24 polymer 5(80) A(5) (1,380) (220)Comparative R-60 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-25polymer 5(80) B(5) (1,380) (220) Comparative R-61 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-26 polymer 5(80) C(5) (1,380) (220)Comparative R-62 Resist PAG- — — — Q-1(2)   SF-1(5) S-1 S-2 Example 1-27polymer 5(80) D(5) (1,380) (220) Comparative R-63 Resist PAG- — — —Q-1(2)   SF-1(5) S-1 S-2 Example 1-28 polymer 5(80) E(5) (1,380) (220)

Note that in Table 1, the solvents, comparative photo-acid generatorsPAG-A to PAG-H, other photo-acid generators PAG-X to PAG-Z, quenchersQ-1 to Q-4, and alkali-soluble surfactant (fluorine-containing polymer)SF-1 are as follows.

PAG-A to PAG-H:

PAG-X to PAG-Z:

SF-1:

Q-1 to Q-4:

Solvents:

S-1: PGMEA (propylene glycol monomethyl ether acetate)

S-2: GBL (γ-butyrolactone)

Surfactant A:

3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane.tetrahydrofuran.2,2-dimethyl-1,3-propanediolcopolymer (available from Omnova Solutions, Inc.)

a:(b+b′):(c+c′)=1:4 to 7:0.01 to 1 (molar ratio)

Mw=1,500

[4] Evaluation of Resist Composition: ArF Exposure Patterning Evaluation(1)

Examples 3-1 to 3-24 and Comparative Examples 2-1 to 2-18

A silicon substrate was coated with an antireflective film solution(ARC29A manufactured by Nissan Chemical Co., Ltd.) and baked forfabrication at 200° C. for 60 seconds to form an antireflective film(film thickness: 100 nm). The antireflective film was spin-coated withone of the resist compositions (R-01 to R-24 and R-36 to R-53), bakedusing a hot plate at 100° C. for 60 seconds to prepare resist filmshaving a film thickness of 90 nm. This was subjected to immersionexposure with a line-and-space pattern (LS pattern) having an on-waferline width of 40 nm and pitch of 80 nm using an ArF excimer laserscanner (NSR-S610C manufactured by Nikon Corporation, NA=1.30, dipolar,Cr mask) while changing the exposure dose and focus (exposure dosepitch: 1 mJ/cm², focus pitch: 0.025 μm). After the exposure, the filmwas baked (PEB) at a temperature shown in Table 3 for 60 seconds. Notethat water was used as the immersion liquid. Then, puddle developmentwas performed with a 2.38 mass % TMAH aqueous solution for 30 seconds,followed by rinsing with pure water and spin drying. Thus, positive typepatterns were obtained. The LS patterns after the development wereobserved with CD-SEM (CG4000) manufactured by Hitachi High-TechnologiesCorporation. The sensitivity, exposure latitude, mask error factor(MEF), line width roughness (LWR), and shape were evaluated according tothe following methods. Table 2 shows the results.

[Sensitivity Evaluation]

As the sensitivity, an optimum exposure dose E_(op) (mJ/cm²) wasdetermined at which an LS pattern with a line width of 40 nm and a pitchof 80 nm was obtained, and this was taken as the sensitivity.

[Exposure Latitude (EL) Evaluation]

In the EL evaluation, EL (unit: %) was determined according to thefollowing equation from exposure doses forming the LS patterns to have aspace width within a range of 40 nm±10% (36 to 44 nm).EL (%)=(|E ₁ −E ₂ |/E _(op))×100

E₁: optimum exposure dose providing an LS pattern with a line width of36 nm and a pitch of 80 nm

E₂: optimum exposure dose providing an LS pattern with a line width of44 nm and a pitch of 80 nm

E_(op): optimum exposure dose providing an LS pattern with a line widthof 40 nm and a pitch of 80 nm

[MEF Evaluation]

The line width of each pattern irradiated at E_(op) was observed withthe pitch fixed and changing the mask dimensions. The slope between themask dimensions and the line width of the pattern was determined as aMEF (Mask Error Enhancement Factor). A MEF of approximately 3.0 or lessis taken to be favorable.

[LWR Evaluation]

The size of the LS pattern obtained by the irradiation at E_(op) wasmeasured at ten positions in a longitudinal direction of the line. Basedon this result, the triple value (3σ) of the standard deviation (σ) wasdetermined as LWR. The smaller the value, the smaller the roughness andthe more uniform the line width of the obtained pattern.

TABLE 2 PEB Eop EL LWR Resist (° C.) (mJ/cm²) (%) MEF (nm) Example 3-1R-1   90 28 19.8 2.2 2.5 Example 3-2 R-2   90 28 19.7 2.6 2.6 Example3-3 R-3   90 28 19.5 2.7 2.8 Example 3-4 R-4   95 28 19.3 2.7 2.7Example 3-5 R-5   95 27 19.5 2.3 2.6 Example 3-6 R-6   95 28 19.8 2.22.6 Example 3-7 R-7   95 29 19.7 2.3 2.6 Example 3-8 R-8   95 27 19.82.6 2.7 Example 3-9 R-9  100 29 19.7 2.5 2.9 Example 3-10 R-10 100 2820.3 2.7 2.4 Example 3-11 R-11 100 29 20.1 2.6 2.5 Example 3-12 R-12  9529 20.3 2.6 2.5 Example 3-13 R-13 100 28 20.0 2.7 2.6 Example 3-14 R-14100 28 19.5 2.7 2.5 Example 3-15 R-15  95 29 19.7 2.8 2.6 Example 3-16R-16  95 28 19.8 2.6 2.6 Example 3-17 R-17  90 30 20.1 2.5 2.5 Example3-18 R-18  90 29 19.7 2.4 2.4 Example 3-19 R-19  90 30 20.0 2.3 2.4Example 3-20 R-20  95 28 19.6 2.5 2.5 Example 3-21 R-21  95 28 19.8 2.62.7 Example 3-22 R-22  95 29 19.9 2.7 2.4 Example 3-23 R-23  90 28 19.82.7 2.3 Example 3-24 R-24  90 27 19.5 2.8 2.2 Comparative R-36  90 2918.0 3.5 3.2 Example 2-1 Comparative R-37  90 28 18.2 3.6 3.5 Example2-2 Comparative R-38  95 30 18.6 3.2 3.3 Example 2-3 Comparative R-39 95 29 18.8 3.4 3.5 Example 2-4 Comparative R-40  95 29 18.0 3.7 3.4Example 2-5 Comparative R-41 100 29 17.9 3.5 3.6 Example 2-6 ComparativeR-42  90 28 17.3 3.6 3.9 Example 2-7 Comparative R-43  95 30 18.2 3.83.5 Example 2-8 Comparative R-44  90 29 18.3 3.9 3.6 Example 2-9Comparative R-45  95 28 18.2 3.4 3.7 Example 2-10 Comparative R-46  9029 17.6 3.5 3.6 Example 2-11 Comparative R-47  90 29 17.9 3.6 3.8Example 2-12 Comparative R-48  95 30 17.8 3.7 3.9 Example 2-13Comparative R-49  95 29 18.1 3.8 3.5 Example 2-14 Comparative R-50  9529 18.0 3.4 3.4 Example 2-15 Comparative R-51  90 28 17.5 3.5 3.2Example 2-16 Comparative R-52  95 29 17.6 3.8 3.3 Example 2-17Comparative R-53  95 29 17.9 3.6 3.5 Example 2-18

From the results shown in Table 2, it is revealed that a resistcomposition containing an onium salt of the present invention as aphoto-acid generator has a favorable sensitivity, is excellent in MEFand LWR, has a favorable pattern shape, and is suitable as material forArF immersion lithography.

On the other hand, the resist compositions (Comparative Examples) thatcontain the conventional photo-acid generators PAG-A to PAG-E (seePatent Documents 1 to 4), PAG-F and PAG-H, whose W₁ does not have aheteroatom, and PAG-G and PAG-H, whose W₂ has a heteroatom, each have alow EL and insufficient MEF and LWR.

[5] Evaluation of Resist Composition: ArF Exposure Patterning Evaluation(2)

Examples 4-1 to 4-11 and Comparative Examples 3-1 to 3-10

Spin-on carbon film ODL-180 (80 mass % of the carbon content)manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a filmthickness of 180 nm, and then, silicon-containing spin-on hard maskSHB-A941 (43 mass % of the silicon content) was formed thereon with afilm thickness of 35 nm to obtain a substrate for a tri-layer process.On the substrate thus prepared, each of the resist compositions (R-25 toR-35 and R54 to R63) was applied by spin coating, and then baked using ahot plate at 100° C. for 60 seconds to form a resist film with a filmthickness of 100 nm. This was subjected to exposure with a contact holepattern (CH pattern) having an on-wafer size of 45 nm and a pitch of 110nm using an ArF excimer laser immersion scanner (NSR-S610C manufacturedby Nikon Corporation, NA=1.30, σ: 0.90/0.72, cross-pole opening degree:35°, Azimuthally polarized illumination, 6% halftone phase shift mask,cross-pole illumination) while changing the exposure dose and focus(exposure dose pitch: 1 mJ/cm², focus pitch: 0.025 μm). After theexposure, PEB was performed at a temperature shown in Table 4 for 60seconds. Note that water was used as the immersion liquid. Then, puddledevelopment was performed with n-butyl acetate for 30 seconds, followedby rinsing with 4-methyl-2-pentanol and spin drying. Thus, negative typepatterns were obtained. The CH patterns after the development wereobserved with CD-SEM (CG4000) manufactured by Hitachi High-TechnologiesCorporation. The sensitivity, MEF, and critical dimension uniformity(CDU) were evaluated according to the following methods. Table 3 showsthe results.

[Sensitivity Evaluation]

As the sensitivity, an optimum exposure dose E_(op) (mJ/cm²) wasdetermined at which a CH pattern with a hole size of 45 nm and a pitchof 110 nm was obtained. The smaller this value, the higher thesensitivity.

[MEF Evaluation]

Each CH pattern irradiated at E_(op) was observed with the pitch fixedand changing the mask dimensions. The slope between the mask dimensionsand the size of the CH pattern was determined as MEF (Mask ErrorEnhancement Factor). A MEF of approximately 3.0 or less is taken to befavorable.

[CDU Evaluation]

The size of the CH pattern obtained by the irradiation at E_(op) wasmeasured at ten positions (nine CH patterns per position) in the singleexposure-dose shot. Based on this result, the triple value (3σ) of thestandard deviation (σ) was determined as critical dimension uniformity(CDU). The smaller the value, the more excellent the critical dimensionuniformity of the CH pattern.

TABLE 3 Eop Resist PEB (° C.) (mJ/cm²) MEF CDU (nm) Example 4-1 R-25 9038 2.4 2.7 Example 4-2 R-26 95 39 2.6 2.6 Example 4-3 R-27 90 38 2.5 2.7Example 4-4 R-28 90 38 2.4 2.8 Example 4-5 R-29 90 37 2.5 2.8 Example4-6 R-30 90 39 2.5 2.6 Example 4-7 R-31 90 38 2.6 2.7 Example 4-8 R-3295 38 2.4 2.7 Example 4-9 R-33 95 40 2.5 2.7 Example 4-10 R-34 90 38 2.52.8 Example 4-11 R-35 100 38 2.6 2.7 Comparative R-54 90 39 3.3 3.9Example 3-1 Comparative R-55 90 38 3.2 3.9 Example 3-2 Comparative R-5690 40 3.1 4.1 Example 3-3 Comparative R-57 95 39 3.4 3.8 Example 3-4Comparative R-58 90 39 3.5 3.7 Example 3-5 Comparative R-59 95 40 3.13.7 Example 3-6 Comparative R-60 100 38 3.2 3.9 Example 3-7 ComparativeR-61 90 38 3.3 3.6 Example 3-8 Comparative R-62 95 38 3.2 3.5 Example3-9 Comparative R-63 90 38 3.2 3.7 Example 3-10

The results shown in Table 3 reveal that the inventive resistcompositions have a favorable sensitivity and are excellent in MEF andCDU in negative patterning by an organic solvent development as well.

On the other hand, the resist compositions (Comparative Examples) thatcontain the conventional photo-acid generators PAG-A to PAG-E (seePatent Documents 1 to 4), PAG-F and PAG-H, whose W₁ does not have aheteroatom, and PAG-G and PAG-H, whose W₂ has a heteroatom, haveinsufficient MEF and CDU.

As explained above, it has been shown that the inventive resistcomposition is also useful in an organic solvent development process.

It should be noted that the present invention is not limited to theabove-described embodiments. The embodiments are just examples, and anyexamples that have substantially the same feature and demonstrate thesame functions and effects as those in the technical concept disclosedin claims of the present invention are included in the technical scopeof the present invention.

The invention claimed is:
 1. A resist composition comprising: (A) aresin containing (i) a repeating unit having an acid-labile group, and(ii) a repeating unit having an aromatic substituent, the repeating unithaving an acid labile group shown by the following general formula (a1):

where R¹ represents a hydrogen atom or a methyl group; and X representsat least one acid-labile group selected from (I) and (II): (I)1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl,1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl,1-tert-butylcyclopentyl, 1-cyclohexylcyclopentyl,1-(4-methoxy-n-butyl)cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl,3-methyl-1-cyclopenten-3-yl, 3-ethyl-1-cyclopenten-3-yl,3-methyl-1-cyclohexen-3-yl, and 3-ethyl-1-cyclohexen-3-yl; (II) groupsshown by the following formulae:

(B) a photo-acid generator that (III) consists of the photo-acidgenerator shown by the general formula (B-1); or (IV) includes acombination of the photo-acid generator shown by the general formula(B-1) and at least one other photo-acid generator selected from thephoto-acid generators shown by general formula (B-2), general formula(B-3), and general formula (B-4); (C) a solvent; and (D) afluorine-containing resin having at least one repeating unit selectedfrom repeating units shown by the general formulas (D-1), (D-2), and(D-3), wherein the fluorine-containing resin is different from the resinof the component (A), General Formula (B-1):

wherein W₁ represents a cyclic divalent hydrocarbon group containing alactone ring structure having 6 to 12 carbon atoms; W₂ represents acyclic monovalent hydrocarbon group having 4 to 14 carbon atoms and notcontaining a heteroatom; Rf represents a divalent organic group shown bythe above general formula; A₁ and A₂ each independently represent ahydrogen atom or a trifluoromethyl group; B₁ and B₂ each independentlyrepresent a hydrogen atom or a fluorine atom; * represents an attachmentpoint for a carbonyloxy group; “m” represents an integer of 0 to 4; “n”represents an integer of 1; and M⁺ represents an onium cation that is atleast one cation selected from the cations of the following formulagroup (b1) and formula group (b2): (i) formula group (b1) is selectedfrom the group consisting of:

formula group (b2) is selected from the group consisting of:

General Formulas (B-2), (B-3), and (B-4):

wherein A¹ represents a hydrogen atom or a trifluoromethyl group; R²¹represents a linear, branched, or cyclic monovalent hydrocarbon grouphaving 1 to 35 carbon atoms optionally containing an oxygen atom, anitrogen-containing heterocyclic group, or a group represented by thefollowing formula (i); M_(B) ⁺ represents the same onium cation as M⁺;

where R³¹ and R³² each independently represent a hydrogen atom, or alinear, branched, or cyclic monovalent hydrocarbon group having 1 to 20carbon atoms optionally containing a heteroatom; R³¹ and R³² optionallybond with each other to form a ring with a nitrogen atom bonded to R³¹and R³²; R³³ represents a linear, branched, or cyclic divalenthydrocarbon group having 1 to 20 carbon atoms optionally containing aheteroatom; wherein A² represents a hydrogen atom or a trifluoromethylgroup; R²², R²³, and R²⁴ each independently represent a hydrogen atom ora linear, branched, or cyclic monovalent hydrocarbon group having 1 to20 carbon atoms optionally containing a heteroatom; “p” and “q” eachindependently represent an integer of 0 to 5; “r” represents an integerof 0 to 4; L represents a single bond, an ether group, or a linear,branched, or cyclic divalent hydrocarbon group having 1 to 20 carbonatoms optionally containing a heteroatom; A³ and A⁴ each independentlyrepresent a hydrogen atom or a trifluoromethyl group, and are not both ahydrogen atom at the same time; and R²⁵ represents a linear, branched,or cyclic monovalent hydrocarbon group having 1 to 35 carbon atomsoptionally containing an oxygen atom, a nitrogen-containing heterocyclicgroup, or a group shown by the formula (i); General Formulas (D-1),(D-2), and (D-3):

wherein R^(A) each independently represent a hydrogen atom or a methylgroup; R⁵¹ and R⁵² each independently represent a hydrogen atom or alinear, branched, or cyclic monovalent hydrocarbon group having 1 to 10carbon atoms; R⁵³ represents a single bond or a linear or brancheddivalent hydrocarbon group having 1 to 5 carbon atoms; R⁵⁴, R⁵⁵, and R⁵⁶each independently represent a hydrogen atom, a linear, branched, orcyclic monovalent hydrocarbon group, fluorinated monovalent hydrocarbongroup, or acyl group having 1 to 15 carbon atoms, or an acid-labilegroup; when R⁵⁴, R⁵⁵, and R⁵⁶ represent the monovalent hydrocarbon groupor the fluorinated monovalent hydrocarbon group, some carbon atomsthereof are optionally substituted with an ether group or a carbonylgroup; R⁵⁷ represents a linear, branched, or cyclic hydrocarbon group orfluorinated hydrocarbon group with a valency of (v+1) having 1 to 20carbon atoms; and “v” represents an integer of 1 to
 3. 2. The resistcomposition according to claim 1, wherein W₂ in the general formula(B-1) represents a polycyclic monovalent hydrocarbon group having 7 to14 carbon atoms and not containing a heteroatom.
 3. The resistcomposition according to claim 2, wherein the group Rf in the generalformula (B-1) is selected from groups shown by the following formulae(Rf-1) and (Rf-3) to (Rf-6),

wherein * represents an attachment point for a carbonyloxy group.
 4. Theresist composition according to claim 1, wherein the group Rf in thegeneral formula (B-1) is selected from groups shown by the followingformulae (Rf-1) and (Rf-3) to (Rf-6),

wherein * represents an attachment point for a carbonyloxy group.
 5. Apatterning process comprising the steps of: forming a resist film bycoating a substrate with the resist composition according to claim 1 andheat-treating; exposing the resist film with a high-energy beam; anddeveloping the exposed resist film using a developer.
 6. The patterningprocess according to claim 5, wherein the high-energy beam is an ArFexcimer laser with a wavelength of 193 nm or a KrF excimer laser with awavelength of 248 nm.
 7. The patterning process according to claim 6,wherein the exposure is an immersion exposure performed with a liquidhaving a refractive index of 1.0 or more placed between the resist filmand a projection lens.
 8. The patterning process according to claim 7,wherein a protective film is further formed on the resist film, andimmersion exposure is performed with the liquid placed between theprotective film and the projection lens.
 9. The patterning processaccording to claim 5, wherein the exposure is an immersion exposureperformed with a liquid having a refractive index of 1.0 or more placedbetween the resist film and a projection lens.
 10. The patterningprocess according to claim 9, wherein a protective film is furtherformed on the resist film, and immersion exposure is performed with theliquid placed between the protective film and the projection lens. 11.The patterning process according to claim 5, wherein the high-energybeam is an electron beam or an extreme ultraviolet ray with a wavelengthof 3 to 15 nm.
 12. The resist composition according to claim 1, whereinthe photo-acid generator (B) is present in the resist composition in anamount of from 0.2 to 40 parts by mass per 100 parts by mass of theresin (A).
 13. The resist composition according to claim 1, wherein thefluorine-containing resin (D) is present in the resist composition in anamount of from 0.5 to 10 parts by mass per 100 parts by mass of theresin (A).
 14. A resist composition comprising: (A) a resin containing(i) a repeating unit having an acid-labile group, and (ii) a repeatingunit having an aromatic substituent, the repeating unit having an acidlabile group shown by the following general formula (a1):

where R¹ represents a hydrogen atom or a methyl group; and X representsat least one acid-labile group selected from (I) and (II): (I)1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl,1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl,1-tert-butylcyclopentyl, 1-cyclohexylcyclopentyl,1-(4-methoxy-n-butyl)cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl,3-methyl-1-cyclopenten-3-yl, 3-ethyl-1-cyclopenten-3-yl,3-methyl-1-cyclohexen-3-yl, and 3-ethyl-1-cyclohexen-3-yl; (II) groupsshown by the following formulae:

(B) a photo-acid generator that (III) consists of the photo-acidgenerator shown by the general formula (B-1); or (IV) includes acombination of the photo-acid generator shown by the general formula(B-1) and at least one other photo-acid generator selected from thephoto-acid generators shown by general formula (B-2), general formula(B-3), and general formula (B-4); (C) a solvent; and (D) afluorine-containing resin having at least one repeating unit selectedfrom repeating units shown by the general formulas (D-1), (D-2), and(D-3), wherein the fluorine-containing resin is different from the resinof the component (A), General Formula (B-1):

wherein W₁ in the general formula (B-1) represents any of cyclicdivalent hydrocarbon groups shown by the following formulae,

wherein * represents an attachment point for a carbonyloxy group,wherein W₂ represents a cyclic monovalent hydrocarbon group having 4 to14 carbon atoms and not containing a heteroatom; Rf represents adivalent organic group shown by the above general formula; A₁ and A₂each independently represent a hydrogen atom or a trifluoromethyl group;B₁ and B₂ each independently represent a hydrogen atom or a fluorineatom; * represents an attachment point for a carbonyloxy group; “m”represents an integer of 0 to 4; “n” represents an integer of 1; and M⁺represents an onium cation that is at least one cation selected from thecations of the following formula group (Ill) and formula group (b2): (i)formula group (b1) is selected from the group consisting of:

formula group (b2) is selected from the group consisting of:

wherein A¹ represents a hydrogen atom or a trifluoromethyl group; R²¹represents a linear, branched, or cyclic monovalent hydrocarbon grouphaving 1 to 35 carbon atoms optionally containing an oxygen atom, anitrogen-containing heterocyclic group, or a group represented by thefollowing formula (i); M_(B) ⁺ represents the same onium cation as M⁺;

where R³¹ and R³² each independently represent a hydrogen atom, or alinear, branched, or cyclic monovalent hydrocarbon group having 1 to 20carbon atoms optionally containing a heteroatom; R³¹ and R³² optionallybond with each other to form a ring with a nitrogen atom bonded to R³¹and R³²; R³³ represents a linear, branched, or cyclic divalenthydrocarbon group having 1 to 20 carbon atoms optionally containing aheteroatom; wherein A² represents a hydrogen atom or a trifluoromethylgroup; R²², R²³, and R²⁴ each independently represent a hydrogen atom ora linear, branched, or cyclic monovalent hydrocarbon group having 1 to20 carbon atoms optionally containing a heteroatom; “p” and “q” eachindependently represent an integer of 0 to 5; “r” represents an integerof 0 to 4; L represents a single bond, an ether group, or a linear,branched, or cyclic divalent hydrocarbon group having 1 to 20 carbonatoms optionally containing a heteroatom; A³ and A⁴ each independentlyrepresent a hydrogen atom or a trifluoromethyl group, and are not both ahydrogen atom at the same time; and R²⁵ represents a linear, branched,or cyclic monovalent hydrocarbon group having 1 to 35 carbon atomsoptionally containing an oxygen atom, a nitrogen-containing heterocyclicgroup, or a group shown by the formula (i); General Formulas (D-1),(D-2), and (D-3):

wherein R^(A) each independently represent a hydrogen atom or a methylgroup; R⁵¹ and R⁵² each independently represent a hydrogen atom or alinear, branched, or cyclic monovalent hydrocarbon group having 1 to 10carbon atoms; R⁵³ represents a single bond or a linear or brancheddivalent hydrocarbon group having 1 to 5 carbon atoms; R⁵⁴, R⁵⁵, and R⁵⁶each independently represent a hydrogen atom, a linear, branched, orcyclic monovalent hydrocarbon group, fluorinated monovalent hydrocarbongroup, or acyl group having 1 to 15 carbon atoms, or an acid-labilegroup; when R⁵⁴, R⁵⁵, and R⁵⁶ represent the monovalent hydrocarbon groupor the fluorinated monovalent hydrocarbon group, some carbon atomsthereof are optionally substituted with an ether group or a carbonylgroup; R⁵⁷ represents a linear, branched, or cyclic hydrocarbon group orfluorinated hydrocarbon group with a valency of (v+1) having 1 to 20carbon atoms; and “v” represents an integer of 1 to
 3. 15. The resistcomposition according to claim 14, wherein W₂ in the general formula(B-1) represents a polycyclic monovalent hydrocarbon group having 7 to14 carbon atoms and not containing a heteroatom.
 16. The resistcomposition according to claim 15, wherein the group Rf in the generalformula (B-1) is selected from groups shown by the following formulae(Rf-1) and (Rf-3) to (Rf-6),

wherein * represents an attachment point for a carbonyloxy group. 17.The resist composition according to claim 14, wherein the group Rf inthe general formula (B-1) is selected from groups shown by the followingformulae (Rf-1) and (Rf-3) to (Rf-6),

wherein * represents an attachment point for a carbonyloxy group.
 18. Apatterning process comprising the steps of: forming a resist film bycoating a substrate with a resist composition and heat-treating; forminga protective film on the resist film; exposing the resist film with ahigh-energy beam by an immersion exposure that is performed with aliquid that is placed between the protective film and a projection lens,the liquid having a refractive index of 1.0 or more; and developing theexposed resist film using a developer, wherein the resist compositioncomprises: (A) a resin containing (i) a repeating unit having anacid-labile group, and (ii) a repeating unit having an aromaticsubstituent, the repeating unit having an acid labile group shown by thefollowing general formula (a1):

where R¹ represents a hydrogen atom or a methyl group; and X representsat least one acid-labile group selected from (I) and (II): (I)1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl,1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl,1-tert-butylcyclopentyl, 1-cyclohexylcyclopentyl,1-(4-methoxy-n-butyl)cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl,3-methyl-1-cyclopenten-3-yl, 3-ethyl-1-cyclopenten-3-yl,3-methyl-1-cyclohexen-3-yl, and 3-ethyl-1-cyclohexen-3-yl; (II) groupsshown by the following formulae:

(B) a photo-acid generator that (III) consists of the photo-acidgenerator shown by the general formula (B-1); or (IV) includes acombination of the photo-acid generator shown by the general formula(B-1) and at least one other photo-acid generator selected from thephoto-acid generators shown by general formula (B-2), general formula(B-3), and general formula (B-4); (C) a solvent; and (D) afluorine-containing resin having at least one repeating unit selectedfrom repeating units shown by the general formulas (D-1), (D-2), and(D-3), wherein the fluorine-containing resin is different from the resinof the component (A), General Formula (B-1):

wherein W₁ represents a cyclic divalent hydrocarbon group having 4 to 12carbon atoms and containing a heteroatom; W₂ represents a cyclicmonovalent hydrocarbon group having 4 to 14 carbon atoms and notcontaining a heteroatom; Rf represents a divalent organic group shown bythe above general formula; A₁ and A₂ each independently represent ahydrogen atom or a trifluoromethyl group; B₁ and B₂ each independentlyrepresent a hydrogen atom or a fluorine atom; * represents an attachmentpoint for a carbonyloxy group; “m” represents an integer of 0 to 4; “n”represents an integer of 1; and M⁺ represents an onium cation that is atleast one cation selected from the cations of the following formulagroup (b1) and formula group (b2): (i) formula group (b1) is selectedfrom the group consisting of:

formula group (b2) is selected from the group consisting of:

General Formulas (B-2), (B-3), and (B-4):

wherein A¹ represents a hydrogen atom or a trifluoromethyl group; R²¹represents a linear, branched, or cyclic monovalent hydrocarbon grouphaving 1 to 35 carbon atoms optionally containing an oxygen atom, anitrogen-containing heterocyclic group, or a group represented by thefollowing formula (i); M_(B) ⁺ represents the same onium cation as M⁺;

where R³¹ and R³² each independently represent a hydrogen atom, or alinear, branched, or cyclic monovalent hydrocarbon group having 1 to 20carbon atoms optionally containing a heteroatom; R³¹ and R³² optionallybond with each other to form a ring with a nitrogen atom bonded to R³¹and R³²; R³³ represents a linear, branched, or cyclic divalenthydrocarbon group having 1 to 20 carbon atoms optionally containing aheteroatom; wherein A² represents a hydrogen atom or a trifluoromethylgroup; R²², R²³, and R²⁴ each independently represent a hydrogen atom ora linear, branched, or cyclic monovalent hydrocarbon group having 1 to20 carbon atoms optionally containing a heteroatom; “p” and “q” eachindependently represent an integer of 0 to 5; “r” represents an integerof 0 to 4; L represents a single bond, an ether group, or a linear,branched, or cyclic divalent hydrocarbon group having 1 to 20 carbonatoms optionally containing a heteroatom; A³ and A⁴ each independentlyrepresent a hydrogen atom or a trifluoromethyl group, and are not both ahydrogen atom at the same time; and R²⁵ represents a linear, branched,or cyclic monovalent hydrocarbon group having 1 to 35 carbon atomsoptionally containing an oxygen atom, a nitrogen-containing heterocyclicgroup, or a group shown by the formula (i); General Formulas (D-1),(D-2), and (D-3):

wherein R^(A) each independently represent a hydrogen atom or a methylgroup; R⁵¹ and R⁵² each independently represent a hydrogen atom or alinear, branched, or cyclic monovalent hydrocarbon group having 1 to 10carbon atoms; R⁵³ represents a single bond or a linear or brancheddivalent hydrocarbon group having 1 to 5 carbon atoms; R⁵⁴, R⁵⁵, and R⁵⁶each independently represent a hydrogen atom, a linear, branched, orcyclic monovalent hydrocarbon group, fluorinated monovalent hydrocarbongroup, or acyl group having 1 to 15 carbon atoms, or an acid-labilegroup; when R⁵⁴, R⁵⁵, and R⁵⁶ represent the monovalent hydrocarbon groupor the fluorinated monovalent hydrocarbon group, some carbon atomsthereof are optionally substituted with an ether group or a carbonylgroup; R⁵⁷ represents a linear, branched, or cyclic hydrocarbon group orfluorinated hydrocarbon group with a valency of (v+1) having 1 to 20carbon atoms; and “v” represents an integer of 1 to
 3. 19. Thepatterning process according to claim 18, wherein the high-energy beamis an ArF excimer laser with a wavelength of 193 nm or a KrF excimerlaser with a wavelength of 248 nm.